staging: rtl8192e: Remove unused RF90_PATH_C and ..D for rfLSSIReadBack

staging: rtl8192e: Remove unused RF90_PATH_C and ..D for rfLSSIReadBack

Remove unused priv->phy_reg_def[RF90_PATH_C].rfLSSIReadBack and
priv->phy_reg_def[RF90_PATH_D].rfLSSIReadBack.
rfLSSIReadBack is used in:
_rtl92e_phy_rf_read which is used in:
rtl92e_set_rf_reg and rtl92e_get_rf_reg are used in:
rtl92e_set_bandwidth (eRFPath only for 0 and 1)
rtl92e_config_rf (eRFPath only for 0 and 1)
_rtl92e_phy_switch_channel_step (eRFPath only for 0 and 1)
_rtl92e_dm_check_tx_power_tracking_thermal (eRFPath only for 0)
rtl92e_check_bb_and_rf is used in:
rtl92e_config_rf (eRFPath only for 0 and 1)
_rtl92e_bb_config_para_file (eRFPath only for 0)
rtl92e_config_rf_path is used in:
rtl92e_config_rf (eRFPath only for 0 and 1)
Remove dead code and constants.

Signed-off-by: Philipp Hortmann <philipp.g.hortmann@gmail.com>
Reviewed-by: Dan Carpenter <error27@gmail.com>
Link: https://lore.kernel.org/r/622777b394a896b6db08eb7faeb455e5cbeae93f.1678569965.git.philipp.g.hortmann@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>