[MMC] sdhci: fix timeout loops in sdhci

The current timeout loop assume that jiffies are updated.  This might not be
the case depending on locks and if the kernel is compiled without preemption.
Change the system to use a counter and fixed delays.

Signed-off-by: Pierre Ossman <drzeus@drzeus.cx>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>