staging: r8188eu: use ETH_ALEN

Use ETH_ALEN instead of hard-coding the value for the mac_addr buffer
in struct eeprom_priv.
Signed-off-by: Michael Straube <straube.linux@gmail.com>
Link: https://lore.kernel.org/r/20210830121508.6411-4-straube.linux@gmail.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/r8188eu/include/rtw_eeprom.h

@@ -99,7 +99,7 @@ struct eeprom_priv {
 	u8		bautoload_fail_flag;
 	u8		bloadfile_fail_flag;
 	u8		bloadmac_fail_flag;
-	u8		mac_addr[6] __aligned(2); /* PermanentAddress */
+	u8		mac_addr[ETH_ALEN] __aligned(2); /* PermanentAddress */
 	u16		channel_plan;
 	u8		EepromOrEfuse;
 	u8		efuse_eeprom_data[HWSET_MAX_SIZE_512] __aligned(4);