Patch from Ben Dooks

The request_irq() function is called by s3c24xx uart driver with
the local IRQs disabled. The request_irq() function can allocate
memory via kmalloc(), and this may sleep causing a warning about
sleeping in an invalid context.
Signed-off-by: NBen Dooks <ben-linux@fluff.org>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>