msm: vidc: Do not call cache operations during map

There is no need to call cache operations while mapping a
buffer. Cache operations are already being called for QBUF
and DQBUF which should suffice.

Change-Id: I32f95d59bffe7bf36254ebe008ccd167729cbac4
Signed-off-by: Vinay Kalia <vkalia@codeaurora.org>