staging: rtl8192u: Fix syntax errors in comments

Delete the redundant word 'tx'.

Signed-off-by: Xiang wangx <wangxiang@cdjrlc.com>
Link: https://lore.kernel.org/r/20220603130702.6926-1-wangxiang@cdjrlc.com


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>