Synaptics Touchpad doesn't support scroll after update to 19.04

I have Lenovo P50 laptop. After upgrading to 19.04 from 18.10 Synaptics touchpad no longer supports scrolling after boot. It is also not detected in 'mouse' settings.

After some research I found that running 'echo -n "reconnect" | sudo tee /sys/bus/serio/devices/serio1/drvctl' seems to fix the problem.

Relevant info in dmesg:

```
$ dmesg | grep -E 'psmouse|i801'
[ 2.101685] i801_smbus 0000:00:1f.4: enabling device (0000 -> 0003)
[ 2.101805] i801_smbus 0000:00:1f.4: SPD Write Disable is set
[ 2.101913] i801_smbus 0000:00:1f.4: SMBus using PCI interrupt
[ 2.871715] psmouse serio1: synaptics: queried max coordinates: x [..5676], y [..4754]
[ 2.905193] psmouse serio1: synaptics: queried min coordinates: x [1266..], y [1100..]
[ 2.905195] psmouse serio1: synaptics: Trying to set up SMBus access
[ 3.109019] i801_smbus 0000:00:1f.4: Timeout waiting for interrupt!
[ 3.109020] i801_smbus 0000:00:1f.4: Transaction timeout
[ 3.111086] psmouse serio1: synaptics: SMbus companion is not ready yet
[ 3.112781] psmouse serio1: synaptics: Unable to initialize device.
```

This is a regression from 18.10 (and all versions before that that I've run on this laptop).

Please let me know if more information is needed. Thanks.

ProblemType: Bug
DistroRelease: Ubuntu 19.04
Package: linux-image-5.0.0-13-generic 5.0.0-13.14
ProcVersionSignature: Ubuntu 5.0.0-13.14-generic 5.0.6
Uname: Linux 5.0.0-13-generic x86_64
NonfreeKernelModules: nvidia_modeset nvidia
ApportVersion: 2.20.10-0ubuntu27
Architecture: amd64
AudioDevicesInUse:
 USER PID ACCESS COMMAND
 /dev/snd/controlC3: kolya 3390 F.... pulseaudio
 /dev/snd/controlC2: kolya 3390 F.... pulseaudio
 /dev/snd/controlC1: kolya 3390 F.... pulseaudio
 /dev/snd/controlC0: kolya 3390 F.... pulseaudio
CurrentDesktop: MATE
Date: Sat May 4 00:17:32 2019
InstallationDate: Installed on 2016-02-20 (1168 days ago)
InstallationMedia: Ubuntu-MATE 15.10 "Wily Werewolf" - Release amd64 (20151021)
MachineType: LENOVO 20EN001SUS
ProcFB: 0 EFI VGA
ProcKernelCmdLine: BOOT_IMAGE=/vmlinuz-5.0.0-13-generic root=/dev/mapper/ubuntu-root ro rootflags=subvol=@ cgroup_enable=memory swapaccount=1 quiet splash vt.handoff=1
RelatedPackageVersions:
 linux-restricted-modules-5.0.0-13-generic N/A
 linux-backports-modules-5.0.0-13-generic N/A
 linux-firmware 1.178
SourcePackage: linux
UpgradeStatus: Upgraded to disco on 2019-05-02 (1 days ago)
dmi.bios.date: 11/14/2018
dmi.bios.vendor: LENOVO
dmi.bios.version: N1EET81W (1.54 )
dmi.board.asset.tag: Not Available
dmi.board.name: 20EN001SUS
dmi.board.vendor: LENOVO
dmi.board.version: Not Defined
dmi.chassis.asset.tag: No Asset Information
dmi.chassis.type: 10
dmi.chassis.vendor: LENOVO
dmi.chassis.version: None
dmi.modalias: dmi:bvnLENOVO:bvrN1EET81W(1.54):bd11/14/2018:svnLENOVO:pn20EN001SUS:pvrThinkPadP50:rvnLENOVO:rn20EN001SUS:rvrNotDefined:cvnLENOVO:ct10:cvrNone:
dmi.product.family: ThinkPad P50
dmi.product.name: 20EN001SUS
dmi.product.sku: LENOVO_MT_20EN_BU_Think_FM_ThinkPad P50
dmi.product.version: ThinkPad P50
dmi.sys.vendor: LENOVO