Documentation: kernel-parameters: fix formatting of MIPS "machtype"

For the "machtype" boot parameter,
fix word spacing, line wrap, and plural of "laptops".

Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Cc: Jiaxun Yang <jiaxun.yang@flygoat.com>
Link: https://lore.kernel.org/r/c9059e35-188d-a749-1907-767b53479328@infradead.org
Signed-off-by: Jonathan Corbet <corbet@lwn.net>