This patch removes the use of the IRQF_DISABLED flag
from drivers/block/hd.c

It's a NOOP since 2.6.35 and it will be removed one day.

This also removes a related comment which is obsolete too.
Signed-off-by: NMichael Opdenacker <michael.opdenacker@free-electrons.com>
Signed-off-by: NJens Axboe <axboe@fb.com>