stm32mp: add function get_cpu_dev

Add a function get_cpu_dev to get the DEV_ID present
in DBGMCU_IDC register.

Signed-off-by: Patrick Delaunay <patrick.delaunay@st.com>
Reviewed-by: Patrice Chotard <patrice.chotard@st.com>
diff --git a/arch/arm/mach-stm32mp/include/mach/sys_proto.h b/arch/arm/mach-stm32mp/include/mach/sys_proto.h
index 1617126..4b6c7b8 100644
--- a/arch/arm/mach-stm32mp/include/mach/sys_proto.h
+++ b/arch/arm/mach-stm32mp/include/mach/sys_proto.h
@@ -20,6 +20,11 @@
 /* return CPU_STMP32MP...Xxx constants */
 u32 get_cpu_type(void);
 
+#define CPU_DEV_STM32MP15	0x500
+
+/* return CPU_DEV constants */
+u32 get_cpu_dev(void);
+
 #define CPU_REVA	0x1000
 #define CPU_REVB	0x2000
 #define CPU_REVZ	0x2001