rtw89: update partition size of firmware header on skb->data

The partition size is used to tell hardware the size of piece we are going
to send a firmware. The old code updates the size in constant buffer of
firmware, and leads system crash.

To fix this, update the size on skb->data after we copy the firmware data
into skb.

Buglink: https://bugzilla.opensuse.org/show_bug.cgi?id=1188303


Fixes: e3ec7017 ("rtw89: add Realtek 802.11ax driver")
Reported-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Ping-Ke Shih <pkshih@realtek.com>
Tested-by: Takashi Iwai <tiwai@suse.de>
Tested-by: Larry Finger <Larry.Finger@lwfinger.net>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Link: https://lore.kernel.org/r/20211119054512.10620-2-pkshih@realtek.com