staging: rtl8723bs: remove RF_*TX enum

remove RF_*TX enum, its only used value is RF_1TX.
So remove it and remove all indexes and loop over
these enum items.

Signed-off-by: Fabio Aiuto <fabioaiuto83@gmail.com>
Link: https://lore.kernel.org/r/3acc624742a933d90e83a83babb4eecb193cf869.1628329348.git.fabioaiuto83@gmail.com


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