msm: vidc: initialize venus hfi locks during hfi creation

Venus hfi locks were initialized during core init,
which is invoked when the first video instance is
created. If a debugfs command is executed before
starting the first video instance, then video driver
crashes trying to lock an uninitialized mutex.

Change-Id: I472e9de91dada94a2728dd02c747e7fde63e3e4f
Signed-off-by: Arun Menon <avmenon@codeaurora.org>