wifi: rtlwifi: rtl8723_common: using calculate_bit_shift()

Using calculate_bit_shift() to replace rtl8723_phy_calculate_bit_shift().
And fix the undefined bitwise shift behavior problem.

Fixes: 0a168b48 ("rtlwifi: rtl8723ae: rtl8723-common: Create new driver for common code")
Signed-off-by: Su Hui <suhui@nfschina.com>
Signed-off-by: Kalle Valo <kvalo@kernel.org>
Link: https://msgid.link/20231219065739.1895666-11-suhui@nfschina.com