devlink: use _BITUL() macro instead of BIT() in the UAPI header

The BIT() macro is not available for the UAPI headers. Moreover, it can
be defined differently in user space headers. Thus, replace its usage
with the _BITUL() macro which is already used in other macro definitions
in <linux/devlink.h>.

Fixes: dc64cc7c ("devlink: Add devlink reload limit option")
Signed-off-by: Tobias Klauser <tklauser@distanz.ch>
Link: https://lore.kernel.org/r/20201215102531.16958-1-tklauser@distanz.ch


Signed-off-by: Jakub Kicinski <kuba@kernel.org>