staging: sm7xx: remove the buggy 2D acceleration support

When scrolling the screen on the console with the 2D acceleration
support, the whole system may hang. for example, when copying some files
from another machine to YeeLoong netbook with the sm7xx video driver via
scp and when the screen output is enabled, the system may hang.

Before the bug is fixed, remove the 2D acceleration!

Signed-off-by: Wu Zhangjin <wuzhangjin@gmail.com>
Cc: Teddy Wang <teddy.wang@siliconmotion.com.cn>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/staging/sm7xx/Kconfig

@@ -6,10 +6,3 @@ config FB_SM7XX
 	select FB_CFB_IMAGEBLIT
 	help
 	  Frame Buffer driver for the Silicon Motion SM7XX serial graphic card.
-
-config FB_SM7XX_ACCEL
-	bool "Siliconmotion Acceleration functions (EXPERIMENTAL)"
-	depends on FB_SM7XX && EXPERIMENTAL
-	help
-	  This will compile the Trident frame buffer device with
-	  acceleration functions.

drivers/staging/sm7xx/TODO

@@ -1,5 +1,6 @@
 TODO:
 - Dual head support
+- 2D acceleration support
 - use kernel coding style
 - checkpatch.pl clean
 - refine the code and remove unused code