net: dsa: qca8k: fix noderef.cocci warnings

drivers/net/dsa/qca8k.c:422:37-43: ERROR: application of sizeof to pointer

sizeof when applied to a pointer typed expression gives the size of
the pointer

Generated by: scripts/coccinelle/misc/noderef.cocci

Fixes: 90386223f44e ("net: dsa: qca8k: add support for larger read/write size with mgmt Ethernet")
CC: Ansuel Smith <[e-mail]>
Reported-by: kernel test robot <[e-mail]>
Signed-off-by: kernel test robot <[e-mail]>
Reviewed-by: Florian Fainelli <[e-mail]>
Link: https://lore.kernel.org/r/20220209221304.GA17529@d2214a582157
Signed-off-by: Jakub Kicinski <[e-mail]>

drivers/net/dsa/qca8k.c

···
 	u16 r1, r2, page;
 	int ret;
 
-	if (!qca8k_read_eth(priv, reg, val, sizeof(val)))
+	if (!qca8k_read_eth(priv, reg, val, sizeof(*val)))
 		return 0;
 
 	qca8k_split_addr(reg, &r1, &r2, &page);