rtlwifi: remove unused variables 'RTL8712_SDIO_EFUSE_TABLE' and 'MAX_PGPKT_SIZE'

drivers/net/wireless/realtek/rtlwifi/efuse.c:16:31:
 warning: RTL8712_SDIO_EFUSE_TABLE defined but not used [-Wunused-const-variable=]
drivers/net/wireless/realtek/rtlwifi/efuse.c:9:17:
 warning: MAX_PGPKT_SIZE defined but not used [-Wunused-const-variable=]

They are never used, so can be removed.

Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>