radeonfb: suspend/resume for ATI Mobility Radeon RV350

Add suspend/resume for the Acer Travelmate 290D/292LMi with the following
graphic-chip:

01:00.0 VGA compatible controller [0300]: ATI Technologies Inc RV350
[Mobility Radeon 9600 M10] [1002:4e50] (prog-if 00 [VGA controller])
	Subsystem: Acer Incorporated [ALI] TravelMate 290 [1025:005a]
	Flags: bus master, 66MHz, medium devsel, latency 128, IRQ 10
	Memory at a8000000 (32-bit, prefetchable) [size=128M]
	I/O ports at c100 [size=256]
	Memory at e0010000 (32-bit, non-prefetchable) [size=64K]
	[virtual] Expansion ROM at a0000000 [disabled] [size=128K]
	Capabilities: [58] AGP version 2.0
	Capabilities: [50] Power Management version 2
	Kernel driver in use: radeonfb
	Kernel modules: radeonfb

Signed-off-by: Wolfgang Kroener <lkml@azog.de>
Cc: Krzysztof Helt <krzysztof.h1@poczta.fm>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>