mdio_bus: coding style fixes

The recent patch from Florian Fainelli fixed all 'checkpatch.pl' errors but left
some warnings like:

- including <asm/io.h> instead of <linux/io.h>;

- including <asm/uaccess.h> instead of <linux/uaccess.h>;

- block comments using empty /* line;

- 'struct dev_pm_ops' variable not being *const*.

While fixing these, also fix the following style issues (some of which were
found running 'checkpatch.pl --strict'):

- alignment not matching open paren;

- file name in the heading comment.

Signed-off-by: Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>
Signed-off-by: David S. Miller <davem@davemloft.net>