asiliantfb: fix cmap memory leaks

- fix cmap leak in removal path
 - fix cmap leak when register_framebuffer fails
 - check return value of fb_alloc_cmap
 - don't continue with driver setup if register_framebuffer fails

[krzysztof.h1@wp.pl: spotted missing iounmap]
[randy.dunlap@oracle.com: move data declaration before any code]
Signed-off-by: Andres Salomon <dilinger@debian.org>
Cc: Krzysztof Helt <krzysztof.h1@wp.pl>
Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>