fb: remove fb_save_state() and fb_restore_state operations

Remove fb_save_state() and fb_restore_state operations from frame buffer layer.
They are used only in two drivers:
1. savagefb  - and cause bug #11248
2. uvesafb

Usage of these operations is misunderstood in both drivers so kill these
operations, fix the bug #11248 and avoid confusion in the future.

Tested on Savage 3D/MV card and the patch fixes the bug #11248.

The frame buffer layer uses these funtions during switch between graphics
and text mode of the console, but these drivers saves state before
switching of the frame buffer (in the fb_open) and after releasing it (in
the fb_release).  This defeats the purpose of these operations.

Addresses http://bugzilla.kernel.org/show_bug.cgi?id=11248



Signed-off-by: Krzysztof Helt <krzysztof.h1@wp.pl>
Reported-by: Jochen Hein <jochen@jochen.org>
Tested-by: Jochen Hein <jochen@jochen.org>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Michal Januszewski <spock@gentoo.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>