staging: r8188eu: the MCS_rate_2R array is not used

The MCS_rate_2R array is not used in the r8188eu driver. Remove it.
Signed-off-by: Martin Kaiser <martin@kaiser.cx>
Link: https://lore.kernel.org/r/20220322202439.157999-3-martin@kaiser.cxSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/r8188eu/core/rtw_mlme.c

@@ -16,7 +16,6 @@
 #include "../include/usb_osintf.h"
 #include "../include/rtl8188e_dm.h"
 
-extern unsigned char	MCS_rate_2R[16];
 extern unsigned char	MCS_rate_1R[16];
 
 void rtw_set_roaming(struct adapter *adapter, u8 to_roaming)

drivers/staging/r8188eu/core/rtw_mlme_ext.c

@@ -71,7 +71,6 @@ extern unsigned char REALTEK_96B_IE[];
 /********************************************************
 MCS rate definitions
 *********************************************************/
-unsigned char	MCS_rate_2R[16] = {0xff, 0xff, 0x0, 0x0, 0x01, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0};
 unsigned char	MCS_rate_1R[16] = {0xff, 0x00, 0x0, 0x0, 0x01, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0};
 
 /********************************************************