is_power_of_2 requires an unsigned long parameter which would
lead to truncation of 64 bit values on 32 bit architectures.

__ffs also expects an unsigned long parameter thus won't work
for 64 bit values on 32 bit architectures.
Signed-off-by: NVarun Sethi <Varun.Sethi@freescale.com>
Tested-by: NEmil Medve <Emilian.Medve@Freescale.com>
Signed-off-by: NJoerg Roedel <jroedel@suse.de>