beaglebone: Drop the obsolete OMAP2_DSS

This kernel option has been dropped by kernel commit 55b68fb856b5
("drm/omap: squash omapdrm sub-modules into one").

Signed-off-by: Kevin Hao <kexin.hao@windriver.com>
Signed-off-by: Bruce Ashfield <bruce.ashfield@gmail.com>

bsp/beaglebone/beaglebone.cfg

@@ -201,7 +201,6 @@ CONFIG_FB_TILEBLITTING=y
 
 #
 # Frame buffer hardware drivers
-CONFIG_OMAP2_DSS=y
 CONFIG_OMAP2_DSS_DPI=y
 CONFIG_OMAP2_DSS_VENC=y
 CONFIG_OMAP2_DSS_DSI=y