mb862xxfb: fix acceleration module license

mb862xxfb_accel built as a separate module, but it does not have a
MODULE_LICENSE, so it taints the kernel.  Add a MODULE_LICENSE to it (same
as mb862xxfb license).

mb862xxfb_accel: module license 'unspecified' taints kernel.

Or should mb862xxfb_accel be built into the mb862xxfb binary file instead?

Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Acked-by: Alexander Shishkin <virtuoso@slind.org>
Cc: Valentin Sitdikov <v.sitdikov@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>