power-domain: Rename free() to rfree()

This function name conflicts with our desire to #define free() to
something else on sandbox. Since it deals with resources, rename it to
rfree().

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Anatolij Gustschin <agust@denx.de>
diff --git a/drivers/power/domain/imx8m-power-domain.c b/drivers/power/domain/imx8m-power-domain.c
index 40ece9e..fbfd177 100644
--- a/drivers/power/domain/imx8m-power-domain.c
+++ b/drivers/power/domain/imx8m-power-domain.c
@@ -121,7 +121,7 @@
 
 struct power_domain_ops imx8m_power_domain_ops = {
 	.request = imx8m_power_domain_request,
-	.free = imx8m_power_domain_free,
+	.rfree = imx8m_power_domain_free,
 	.on = imx8m_power_domain_on,
 	.off = imx8m_power_domain_off,
 	.of_xlate = imx8m_power_domain_of_xlate,