cirrusfb: fix Laguna chipset memory detection and clock setting

cirrusfb: fix Laguna chipset memory detection and clock setting

Fix memory detection and clock setting for Cirrus Laguna chipsets
(GD5464/GD5465).  The changes are done after the Xorg code.

The driver still does not display anything on the GD5465 but it switches
resolutions correctly at least.

Signed-off-by: Krzysztof Helt <krzysztof.h1@wp.pl>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>