The prefix suggests the number should be printed in hex, so use
the %x specifier to do that.

Found by using regex suggested by Joe Perches.
Signed-off-by: NHans Wennborg <hans@hanshq.net>
Acked-by: NAvinash Patil <patila@marvell.com>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>