MIPS: Octeon: mangle-port: fix build failure with VDSO code

MIPS: Octeon: mangle-port: fix build failure with VDSO code

Commit 1685ddbe35cd ("MIPS: Octeon: Changes to support readq()/writeq()
usage.") added bitwise shift operations that assume that unsigned long
is always 64-bits. This broke the build of VDSO code, as it gets compiled
also in "faked" 32-bit mode. Althought the failing inline functions are
never executed in 32-bit mode, they still need to pass the compilation.
Fix by using 64-bit types explicitly.

The patch fixes the following build failure:

  CC      arch/mips/vdso/gettimeofday-o32.o
In file included from los/git/devel/linux/arch/mips/include/asm/io.h:32:0,
                 from los/git/devel/linux/arch/mips/include/asm/page.h:194,
                 from los/git/devel/linux/arch/mips/vdso/vdso.h:26,
                 from los/git/devel/linux/arch/mips/vdso/gettimeofday.c:11:
los/git/devel/linux/arch/mips/include/asm/mach-cavium-octeon/mangle-port.h: In function '__should_swizzle_bits':
los/git/devel/linux/arch/mips/include/asm/mach-cavium-octeon/mangle-port.h:19:40: error: right shift count >= width of type [-Werror=shift-count-overflow]
  unsigned long did = ((unsigned long)a >> 40) & 0xff;
                                        ^~

Fixes: 1685ddbe35cd ("MIPS: Octeon: Changes to support readq()/writeq() usage.")
Signed-off-by: Aaro Koskinen <aaro.koskinen@iki.fi>
Acked-by: David Daney <ddaney@caviumnetworks.com>
Cc: David Daney <david.daney@cavium.com>
Cc: Steven J. Hill <steven.hill@cavium.com>
Cc: Alex Smith <alex.smith@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/14039/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>