PCI: rcar: Fix calculating mask for PCIEPAMR register

The mask value was calculated incorrectly for PCIEPAMR register if the
size was less than 128 bytes. Fix this issue by adding a check on size.

Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Lad Prabhakar <[e-mail]>
Signed-off-by: Lorenzo Pieralisi <[e-mail]>
Reviewed-by: Yoshihiro Shimoda <[e-mail]>

drivers/pci/controller/pcie-rcar.c

···
 	 * keeps things pretty simple.
 	 */
 	size = resource_size(res);
-	mask = (roundup_pow_of_two(size) / SZ_128) - 1;
+	if (size > 128)
+		mask = (roundup_pow_of_two(size) / SZ_128) - 1;
+	else
+		mask = 0x0;
 	rcar_pci_write_reg(pcie, mask << 7, PCIEPAMR(win));
 
 	if (res->flags & IORESOURCE_IO)