msm:camera: Fix signedness issue in hw_exec_cmds

  In hw_exec_cmds()second argument m_cmds should be
  of type unsigned interger

Change-Id: Idad2eb1a59481f3fe9f90221ff2061e8dae57013
CRs-Fixed: 493314
Signed-off-by: Monika Alekhya <malekh@codeaurora.org>