stm32mp1: Add check on syscon_get_first_range() return value

syscon_get_first_range()'s return value is used as base address to perform
a read, without any checks.
In case stmp32mp_syscon is not binded, syscon_get_first_range() returns
-ENODEV which leads to a "Synchronous abort".

Add syscon_get_first_range() check on return value.

Signed-off-by: Patrice Chotard <patrice.chotard@foss.st.com>
Reviewed-by: Patrick Delaunay <patrick.delaunay@foss.st.com>

arch/arm/mach-stm32mp/stm32mp1/stm32mp13x.c

@@ -17,6 +17,7 @@
 #include <dm/device.h>
 #include <dm/uclass.h>
 #include <linux/bitfield.h>
+#include <linux/err.h>
 #include <malloc.h>
 
 /* RCC register */
@@ -231,6 +232,12 @@ static u32 read_idc(void)
 {
 	void *syscfg = syscon_get_first_range(STM32MP_SYSCON_SYSCFG);
 
+	if (IS_ERR(syscfg)) {
+		pr_err("Error, can't get SYSCON range (%ld)\n", PTR_ERR(syscfg));
+
+		return PTR_ERR(syscfg);
+	}
+
 	return readl(syscfg + SYSCFG_IDC_OFFSET);
 }