net: ks8851: Inline ks8851_rx_skb()

Both ks8851_rx_skb_par() and ks8851_rx_skb_spi() call netif_rx(skb),
inline the netif_rx(skb) call directly into ks8851_common.c and drop
the .rx_skb callback and ks8851_rx_skb() wrapper. This removes one
indirect call from the driver, no functional change otherwise.

Signed-off-by: Marek Vasut <marex@denx.de>
Link: https://lore.kernel.org/r/20240405203204.82062-1-marex@denx.de


Signed-off-by: Jakub Kicinski <kuba@kernel.org>