wifi: rtw89: 8852c: update supported firmware format to 2

After firmware 0.27.125.0, it adds more fields to support firmware secure
boot. Though current driver has supported the format, old driver can't
recognize the new format, increase firmware format to 2 to avoid failed
to load the firmware by old driver.

Signed-off-by: Ping-Ke Shih <pkshih@realtek.com>
Link: https://patch.msgid.link/20250416081241.36138-2-pkshih@realtek.com