rtw88: rtw8822c: eliminate code duplication, use native swap() function

swap_u32() duplicate native swap(), so replace swap_u32() with swap().

Signed-off-by: Ivan Safonov <insafonov@gmail.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Link: https://lore.kernel.org/r/20200913165958.419744-1-insafonov@gmail.com