rtlwifi: rtl8723be: Remove set but not used variables 'reg_ecc','reg_eac'

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

drivers/net/wireless/realtek/rtlwifi/rtl8723be/phy.c: In function rtl8723be_phy_iq_calibrate:
drivers/net/wireless/realtek/rtlwifi/rtl8723be/phy.c:2255:7: warning: variable reg_ecc set but not used [-Wunused-but-set-variable]
drivers/net/wireless/realtek/rtlwifi/rtl8723be/phy.c: In function rtl8723be_phy_iq_calibrate:
drivers/net/wireless/realtek/rtlwifi/rtl8723be/phy.c:2254:34: warning: variable reg_eac set but not used [-Wunused-but-set-variable]

They are not used since commit a619d1ab ("rtlwifi:
rtl8723be: Add new driver")

Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: zhengbin <zhengbin13@huawei.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>