ARM: assembler.h: use same WRITE_ALIGN_BYTES on omap4 as on armv6 platforms

Not all armv7 have 64 kbytes of l1 cache, for example the
Cortex-A9, which has 32 kbytes. As all omap4 platforms also
run Cortex-A9, adjust WRITE_ALIGN_BYTES accordingly.

Still needs testing.
defconfig: 3G/1G vmsplit (tuna default)
fs/dcache.c: vfs_cache_pressure = 65
mm.h: default read_ahead_kb to 256
blkdev.h: default nr_requests to 256
Linux 3.0.95
Tuna: add option to reclaim ~73 MB of reserved RAM (HUGEMEM)

Reclaim 69M of RAM from HEAP_TILER and 4M from the OMAP
framebuffer. This will break 1080p video recording and
some camera functionalities, unless 1080p modes are
disabled from within /system/etc/media_profiles.xml.

Credits go to mpokwsths.
defconfig (ext): enable TUNA_HUGEMEM
Fancy Kernel r41