MIPS: replace MBIT_ULL() with BIT_ULL()

Commit 8bd9cb51 ("locking/atomics, asm-generic: Move some macros
from <linux/bitops.h> to a new <linux/bits.h> file") moved BIT_ULL()
into <linux/bits.h>. It only includes <asm/bitsperlong.h>, so there is
no longer "include file recursion hell".

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Paul Burton <paul.burton@mips.com>
Cc: linux-mips@vger.kernel.org
Cc: James Hogan <jhogan@kernel.org>
Cc: Huacai Chen <chenhc@lemote.com>
Cc: linux-kernel@vger.kernel.org
Cc: Ralf Baechle <ralf@linux-mips.org>