gsm_data_alloc buffer allocation could fail and it is not being checked.

Add check for allocated buffer and return if the buffer allocation
fails.
Signed-off-by: NKen Mills <ken.k.mills@intel.com>
Signed-off-by: NAlan Cox <alan@linux.intel.com>
Cc: stable@kernel.org
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>