wifi: rtw89: 8852ce: fix gray code conversion for filter out EQ

To use manual mode to set value of filter out EQ, read the source value of
filter out EQ coded in gray code, and write to the target register in
binary number. The function to convert from gray code to binary number is
wrong originally, causing unexpected EQ, so fix it.

Signed-off-by: Ping-Ke Shih <pkshih@realtek.com>
Link: https://patch.msgid.link/20240925013901.9835-4-pkshih@realtek.com