wifi: rtw89: debug: fix error code in rtw89_debug_priv_send_h2c_set()

wifi: rtw89: debug: fix error code in rtw89_debug_priv_send_h2c_set()

If there is a failure during rtw89_fw_h2c_raw() rtw89_debug_priv_send_h2c
should return negative error code instead of a positive value count.
Fix this bug by returning correct error code.

Fixes: e3ec7017f6a2 ("rtw89: add Realtek 802.11ax driver")
Signed-off-by: Zhang Shurong <zhang_shurong@foxmail.com>
Acked-by: Ping-Ke Shih <pkshih@realtek.com>
Link: https://lore.kernel.org/r/tencent_AD09A61BC4DA92AD1EB0790F5C850E544D07@qq.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>