drivers/char/msm_smd_pkt.c: don't use IS_ERR()

The various basic memory allocation function return NULL, not an
ERR_PTR.

The semantic patch that makes this change is available in
scripts/coccinelle/null/eno.cocci.

More information about semantic patching is available at
http://coccinelle.lip6.fr/

Signed-off-by: Thomas Meyer <thomas@m3y3r.de>
Cc: Niranjana Vishwanathapura <nvishwan@codeaurora.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>