msm: smd_pkt: Support multiplatform

Upstream prefers existing drivers be converted to support multiplatform
kernels.  This requires drivers to be located in generic functionality
directories instead of specific mach directories.

Move the smd_pkt driver to the drivers/char location to support
multiplatform.

Change-Id: I0a05d27171a47a985cb5934d0df1d982b7cbc139
Signed-off-by: Jeffrey Hugo <jhugo@codeaurora.org>