camera: typo fix in file operations handlers

I have registered msm_open_frame as open handler for config0
(instead of msm_open) and vice versa for frame0.
This commit fixes this issue.
camera: fix crash on closing preview

The client_for_ion has been initialized each time the control0,
config0 or frame0 has been opened and released when closing one
of them.
This made that the ion allocations has been made using different
ion client than when freeing them which resulted in kernel oops.
This patch creates client_for_ion once when loading module and
frees it when unloading the module.
This increases the kernel memory usage by keeping the ion client
instance for the module lifetime instead of allocating it only
when it will be needed but at least the kernel crash is being fixed.
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