wifi: rtw89: mac: differentiate mem_page_size by chip generation

When debugging or recovering system error recovery (SER), it's
necessary to dump internal memory to perform status inspection.
Since the memory page size differs between WiFi 6 and 7 chips,
define them accordingly.

Signed-off-by: Kuan-Chung Chen <damon.chen@realtek.com>
Signed-off-by: Ping-Ke Shih <pkshih@realtek.com>
Link: https://patch.msgid.link/20250618124649.11436-2-pkshih@realtek.com