[PATCH] add support for loading OMAP bootrom from file for booting

This patch adds support of loading bootrom for OMAP3 platform from
 file, for booting.
 Here is example, how-to use qemu with it:

 qemu-system-arm -M n900 -m 256 -L . -bios bootrom.bin -mtdblock
 bootloader.raw -d in_asm,cpu,exec -nographic

 Right now it only placed in GPMC memory region. But need to be
 implemented with independend OCM (On-Chip Memory) controller.
 Because, when bootrom call GPMC init function (there is place, where
 it filling by zeroes, so rewrite bootrom, in memory). This need to be
 fixed. Right now it can be easy skipped with gdb.

 Here is use case https://www.droid-developers.org/wiki/QEMU