[PATCH] ARM: switch fd1772.c from sleep_on to wait_event

Doesn't make the local irq disabling around it less buggy, but at
least we replace the offender with the right kind of primitive.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>