feat(stm32mp1): get CPU info from SYSCFG on STM32MP13

The IDC register from DBGMCU is duplicated in SYSCFG. As SYSCFG is
always accessible, get chip ID and revision ID from there on STM32MP13.

Change-Id: Ib0b6e8f68a2934a45ec0012f69db6c12a60adb17
Signed-off-by: Yann Gautier <yann.gautier@st.com>
diff --git a/plat/st/stm32mp1/include/stm32mp1_private.h b/plat/st/stm32mp1/include/stm32mp1_private.h
index 38de1b7..7bdb36d 100644
--- a/plat/st/stm32mp1/include/stm32mp1_private.h
+++ b/plat/st/stm32mp1/include/stm32mp1_private.h
@@ -21,6 +21,8 @@
 void stm32mp1_syscfg_enable_io_compensation_start(void);
 void stm32mp1_syscfg_enable_io_compensation_finish(void);
 void stm32mp1_syscfg_disable_io_compensation(void);
+uint32_t stm32mp1_syscfg_get_chip_version(void);
+uint32_t stm32mp1_syscfg_get_chip_dev_id(void);
 
 void stm32mp1_deconfigure_uart_pins(void);