mips: Convert pr_warning to pr_warn

Use the much more common pr_warn instead of pr_warning
with the goal of removing pr_warning eventually.

Other miscellanea:

o Coalesce formats
o Realign arguments

Signed-off-by: Joe Perches <joe@perches.com>
Cc: linux-mips <linux-mips@linux-mips.org>
Cc: LKML <linux-kernel@vger.kernel.org>
Patchwork: https://patchwork.linux-mips.org/patch/7935/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>