mfd: qcom-spmi-pmic: Don't access non-existing registers

Revision ID registers are available only on devices with
Slave IDs that are even, so don't make access to unavailable
registers.
Signed-off-by: NIvan T. Ivanov <ivan.ivanov@linaro.org>
[sboyd@codeaurora.org: Consider all slave ids that are even]
Signed-off-by: NStephen Boyd <sboyd@codeaurora.org>
Signed-off-by: NLee Jones <lee.jones@linaro.org>

drivers/mfd/qcom-spmi-pmic.c

@@ -127,7 +127,9 @@ static int pmic_spmi_probe(struct spmi_device *sdev)
 	if (IS_ERR(regmap))
 		return PTR_ERR(regmap);
 
-	pmic_spmi_show_revid(regmap, &sdev->dev);
+	/* Only the first slave id for a PMIC contains this information */
+	if (sdev->usid % 2 == 0)
+		pmic_spmi_show_revid(regmap, &sdev->dev);
 
 	return of_platform_populate(root, NULL, NULL, &sdev->dev);
 }