staging: rtl8723au: Remove unneeded comments

This commit removes a number of unneeded comments. Two of the
aforementioned comments were most likely meant to aid with version
control, whereas the remaining two comments relate to (now unused)
local variable names.

Signed-off-by: M. Vefa Bicakci <m.v.b@runbox.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>