rtl818x_pci: Remove set but not used variables 'io_addr, mem_addr'

Fixes gcc '-Wunused-but-set-variable' warning:

drivers/net/wireless/realtek/rtl818x/rtl8180/dev.c: In function 'rtl8180_probe':
drivers/net/wireless/realtek/rtl818x/rtl8180/dev.c:1727:15: warning:
 variable 'io_addr' set but not used [-Wunused-but-set-variable]

drivers/net/wireless/realtek/rtl818x/rtl8180/dev.c:1726:16: warning:
 variable 'mem_addr' set but not used [-Wunused-but-set-variable]

They're never used since introduction.

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