char: msm_smd_pkt: Remove hexdump of userspace read/write buffers

Dumping userspace read/write buffers without first copying the data may
lead to a kernel panic if the buffer is unmapped after the buffer has
been validated but before the VFS call returns.

Remove the debug code to print the data using userspace buffers.

CRs-Fixed: 730626
Change-Id: I95c0d751121812fd5d5f30e2b4ee221b1fc36083
Signed-off-by: Arun Kumar Neelakantam <aneela@codeaurora.org>
Signed-off-by: Eric Holmberg <eholmber@codeaurora.org>