camera: fix signedness issue in hw_exec_cmds (CVE-2013-4736)

This is part of the commit:
https://www.codeaurora.org/cgit/quic/la//kernel/msm/commit/?id=81947189009afcfac17d1106101260c660421265
camera: Fix overflow issue in ioctl_hw_cmds function (CVE-2013-4736)

This is part of commit:
https://www.codeaurora.org/cgit/quic/la//kernel/msm/commit/?id=8c5300aec8cd9882b89e9d169680221541da0d7f
Enable pmem_adsp allocator for msm camera
camera: do not allocate client_for_ion when ION is disabled