input: cyttsp-i2c-qc: Add mutex_init call before chip init

Chip initialization routine registers device files to upgrade
firmware. The firmware upgrade routine uses mutex for locking
but as mutex is initialized after chip init we see some random
crashes. Fix this issue by calling mutex_init() before
cyttsp_initialize().

Change-Id: I34afdb04b1ea8a9912fff998128b26a309346e9b
Signed-off-by: Mohan Pallaka <mpallaka@codeaurora.org>