Staging: rtl8192e: Rename variable TxSTBC

Rename variable TxSTBC to tx_stbc
to fix checkpatch warning Avoid CamelCase.

Signed-off-by: Tree Davies <tdavies@darkphysics.net>
Tested-by: Philipp Hortmann <philipp.g.hortmann@gmail.com>
Link: https://lore.kernel.org/r/20240428230106.6548-12-tdavies@darkphysics.net


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