[PATCH] radeonfb: don't blow up VGA console on load

The current radeonfb memset's the framebuffer to 0 when loaded.  This
removes occasional artifacts but has the nasty side effect that if you
load radeonfb without framebuffer console, you destroy the VGA text
buffer, font, etc...  radeon must not touch the framebuffer content when
it doesn't "own" it.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>