acpi: Use pr_warn instead of pr_warning

acpi: Use pr_warn instead of pr_warning

As said in commit f2c2cbcc35d4 ("powerpc: Use pr_warn instead of
pr_warning"), removing pr_warning so all logging messages use a
consistent <prefix>_warn style. Let's do it.

Link: http://lkml.kernel.org/r/20191018031850.48498-8-wangkefeng.wang@huawei.com
To: linux-kernel@vger.kernel.org
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Cc: Len Brown <lenb@kernel.org>
Cc: James Morse <james.morse@arm.com>
Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Reviewed-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
[pmladek@suse.com: two more indentation fixes]
Signed-off-by: Petr Mladek <pmladek@suse.com>