pinctrl: renesas: rzg2l: Return -EINVAL for pins which have input disabled

Pin status reported by pinconf-pins file always reported pin status as
"input enabled" even for pins which had input disabled. Fix this by
returning -EINVAL for the pins which have input disabled.

Fixes: c4c4637eb57f2 ("pinctrl: renesas: Add RZ/G2L pin and gpio controller driver")
Reported-by: Phil Edworthy <[e-mail]>
Signed-off-by: Lad Prabhakar <[e-mail]>
Reviewed-by: Phil Edworthy <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Geert Uytterhoeven <[e-mail]>

drivers/pinctrl/renesas/pinctrl-rzg2l.c

···
 		if (!(cfg & PIN_CFG_IEN))
 			return -EINVAL;
 		arg = rzg2l_read_pin_config(pctrl, IEN(port_offset), bit, IEN_MASK);
+		if (!arg)
+			return -EINVAL;
 		break;
 
 	case PIN_CONFIG_POWER_SOURCE: {