This driver shows warnings on many architectures:

drivers/isdn/sc/init.c: In function 'identify_board':
drivers/isdn/sc/init.c:484:2: error: passing argument 1 of 'readl' makes pointer from integer without a cast [-Werror]

In newer kernels, it was completely removed, but for the 4.4-stable
series, let's just shut up that warning by adding an extra variable
to do the necessary type cast.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>