wifi: rtw89: fix physts IE page check

The index RTW89_PHYSTS_BITMAP_NUM is not a valid physts IE page.
So, fix the check condition.

Fixes: eb4e52b3

 ("rtw89: fix incorrect channel info during scan")
Signed-off-by: Zong-Zhe Yang <kevin_yang@realtek.com>
Signed-off-by: Ping-Ke Shih <pkshih@realtek.com>
Signed-off-by: Kalle Valo <kvalo@kernel.org>
Link: https://lore.kernel.org/r/20221118042322.26794-1-pkshih@realtek.com