net: stmmac: make variable data a u32

Make data a u32 instead of an unsigned long, this way it is
explicitly the same width as the operations performed on it
and the same width as a writel store, and it cleans up sign
extention warnings when 64 bit static analysis is performed
on the code.

Signed-off-by: Colin Ian King <[e-mail]>
Reviewed-by: Russell King (Oracle) <[e-mail]>
Link: https://patch.msgid.link/[e-mail]
Signed-off-by: Jakub Kicinski <[e-mail]>

drivers/net/ethernet/stmicro/stmmac/dwmac_lib.c

···
 void stmmac_set_mac_addr(void __iomem *ioaddr, const u8 addr[6],
 			 unsigned int high, unsigned int low)
 {
-	unsigned long data;
+	u32 data;
 
 	data = (addr[5] << 8) | addr[4];
 	/* For MAC Addr registers we have to set the Address Enable (AE)