xfs: Fix 64-bit division on 32-bit in xlog_state_switch_iclogs()

On 32-bit (e.g. m68k):

    ERROR: modpost: "__udivdi3" [fs/xfs/xfs.ko] undefined!

Fix this by using a uint32_t intermediate, like before.

Reported-by:  <noreply@ellerman.id.au>
Fixes: 7660a5b48fbef958 ("xfs: log stripe roundoff is a property of the log")
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Darrick J. Wong <djwong@kernel.org>