staging: rtl8192ee: Correct bitmask in comparsion

The issue is discovered by static checker. The proposed change (0x000c0
-> 0x000c) is likely correct because:
1. 16-bit `map` holds value coming from struct
ieee80211_vht_mcs_info.tx_mcs_map, which is described so: "TX MCS map 2
bits for each stream, total 8 streams". The changed code refers to case
of 2 TX streams, and 0x000c mask filters two bits related to the second
stream. Some codelines below 0x0003 mask is used to test first stream.
2. Mask 0x000c is used 3 more times in that place.
3. Specifying 5 digits of hex value is uncommon, especially while working
with `u16` variable. So likely the trailing zero is a typo.

Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=78041


Reported-by: David Binderman <dcb314@hotmail.com>
Signed-off-by: Andrey Utkin <andrey.krieger.utkin@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>