mips: octeon: cvmx-pkoh: fix duplicated words

Delete the repeated word "command".
Delete the repeated words "returns" and convert to kernel-doc notation
by adding a ':'.

Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: linux-mips@vger.kernel.org
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>