ion: ioctl compatibility with userland using old api

As far as I can tell, flags passed by userland are now used to determine
buffer caching.

Note in ION_IOC_ALLOC_COMPAT we are currently forcing uncached buffer
allocations (needed to make a choice here).  This
may need to change.

Signed-off-by: Flemmard <flemmard@gmail.com>

Conflicts:
	include/linux/ion.h
	include/linux/msm_ion.h