Otherwise it can only take the values 0/-1 which doesn't seem to
have been intended.

drivers/mmc/host/sdhci.h:190:20: error: dubious one-bit signed bitfield
Signed-off-by: NHarvey Harrison <harvey.harrison@gmail.com>
Acked-by: NPierre Ossman <drzeus-list@drzeus.cx>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>