rtl8712: don't duplicate ieee80211 constants for status/reason

These are all defined as a part of the standard and should not be
duplicated on a per-driver basis.  Use the global ones and delete the
local ones.

It seems that ieee80211 was already included everywhere it was needed,
since no explicit include <...> were needed to be added in order to
preserve getting a successful compile.

This isn't the totality of duplicated data removed, but it is a start.

Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>