staging: r8188eu: max_rx_ampdu_factor is always MAX_AMPDU_FACTOR_64K

staging: r8188eu: max_rx_ampdu_factor is always MAX_AMPDU_FACTOR_64K

The local variable max_rx_ampdu_factor in rtw_restructure_ht_ie() and
issue_action_BA() is always set to MAX_AMPDU_FACTOR_64K. Remove the
variable from both functions and use MAX_AMPDU_FACTOR_64K directly.

The case HW_VAR_MAX_RX_AMPDU_FACTOR in GetHalDefVar8188EUsb() is now
unused and can be removed.

Signed-off-by: Michael Straube <straube.linux@gmail.com>
Link: https://lore.kernel.org/r/20220128115445.6606-4-straube.linux@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>