drm-next build fail with gcc 4.6.3

[Andy Furniss]

   CC      drivers/video/console/vgacon.o
drivers/video/console/vgacon.c: In function ‘vgacon_do_font_op’:
drivers/video/console/vgacon.c:1129:5: error: implicit declaration of 
function ‘cond_resched’ [-Werror=implicit-function-declaration]
cc1: some warnings being treated as errors
make[3]: *** [drivers/video/console/vgacon.o] Error 1