powercap: RAPL: Fix a NULL vs IS_ERR() bug

The devm_ioremap_resource() function returns error pointers on error,
it never returns NULL. Update the check accordingly.

Fixes: 9eef7f9da928 ("powercap: intel_rapl: Introduce RAPL TPMI interface driver")
Signed-off-by: Dan Carpenter <[e-mail]>
Acked-by: Zhang Rui <[e-mail]>
Signed-off-by: Rafael J. Wysocki <[e-mail]>

drivers/powercap/intel_rapl_tpmi.c

···
 	}
 
 	trp->base = devm_ioremap_resource(&auxdev->dev, res);
-	if (!trp->base) {
-		ret = -ENOMEM;
+	if (IS_ERR(trp->base)) {
+		ret = PTR_ERR(trp->base);
 		goto err;
 	}