msm: kgsl: set usermem type in the memdesc flags

It is sometimes helpful for userspace to know if
a buffer is allocated memory or mapped in from
another driver. Add  KGSL_MEMFLAGS_USERMEM_ values
so this information can be stored into the flags,
which are visible to userspace after the allocation
and map ioctls return, or via IOCTL_KGSL_GPUMEM_GET_INFO.

Because enum kgsl_user_mem_type only accounted for
mapped memory types, the flags value adds 1 to each
enum so that 0 can mean allocated (not mapped)
memory.

Change-Id: I1af71ca5527adb4bae04cfe003afa7d4db1d0a21
Signed-off-by: Jeremy Gebben <jgebben@codeaurora.org>