arm: imx9: Call imx9_probe_mu for DM post in board_r

This event callback imx9_probe_mu needs to be called in board_r
as well, because many ELE APIs depending on this MU probed

Signed-off-by: Ye Li <ye.li@nxp.com>
diff --git a/arch/arm/mach-imx/imx9/soc.c b/arch/arm/mach-imx/imx9/soc.c
index e2794d6..2117489 100644
--- a/arch/arm/mach-imx/imx9/soc.c
+++ b/arch/arm/mach-imx/imx9/soc.c
@@ -622,6 +622,7 @@
 	return 0;
 }
 EVENT_SPY_SIMPLE(EVT_DM_POST_INIT_F, imx9_probe_mu);
+EVENT_SPY_SIMPLE(EVT_DM_POST_INIT_R, imx9_probe_mu);
 
 int timer_init(void)
 {