sm501: fixes for akpms comments on gpiolib addition

Fixup the comments from the patch that added the gpiolib support from
Andrew Morton.  These include spotting some missing frees on error or
release, and changing a memcpy for a type-safe assingment.

Signed-off-by: Ben Dooks <ben-linux@fluff.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>