brcmfmac: Remove unused macro.

This macro is used exactly nowhere in the code. Delete it.
Signed-off-by: Ian Molton <ian@mnementh.co.uk>
Reviewed-by: Arend van Spriel <arend.vanspriel@broadcom.com>
Signed-off-by: Arend van Spriel <arend.vanspriel@broadcom.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>

drivers/net/wireless/broadcom/brcm80211/brcmfmac/sdio.c

@@ -159,8 +159,6 @@ struct rte_console {
 /* manfid tuple length, include tuple, link bytes */
 #define SBSDIO_CIS_MANFID_TUPLE_LEN	6
 
-#define CORE_BUS_REG(base, field) \
-		(base + offsetof(struct sdpcmd_regs, field))
 #define SD_REG(field) \
 		(offsetof(struct sdpcmd_regs, field))