Do not use memcpy in fb_pad_aligned_buffer.  It is suboptimal because only
a few bytes are moved at a time.  Replace with a for-loop.

Signed-off-by: Antonino Daplas <adaplas@pol.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>