fix(plat/st): correct IO compensation disabling

In stm32mp1_syscfg_disable_io_compensation(), to disable the IO
compensation cell, we have to set the corresponding bit in
SYSCFG_CMPENCLRR register, instead of clearing the bit in SETR register.

Change-Id: I510a50451f8afb9e98c24e1ea84efbf73a39e6b4
Signed-off-by: Yann Gautier <yann.gautier@st.com>

plat/st/stm32mp1/stm32mp1_syscfg.c

 /*
- * Copyright (c) 2019-2020, STMicroelectronics - All Rights Reserved
+ * Copyright (c) 2019-2021, STMicroelectronics - All Rights Reserved
  *
  * SPDX-License-Identifier: BSD-3-Clause
  */
@@ -22,6 +22,7 @@
 #define SYSCFG_ICNR				0x1CU
 #define SYSCFG_CMPCR				0x20U
 #define SYSCFG_CMPENSETR			0x24U
+#define SYSCFG_CMPENCLRR			0x28U
 
 /*
  * SYSCFG_BOOTR Register
@@ -167,8 +168,7 @@ void stm32mp1_syscfg_disable_io_compensation(void)
 
 	mmio_write_32(SYSCFG_BASE + SYSCFG_CMPCR, value | SYSCFG_CMPCR_SW_CTRL);
 
-	mmio_clrbits_32(SYSCFG_BASE + SYSCFG_CMPENSETR,
-			SYSCFG_CMPENSETR_MPU_EN);
+	mmio_setbits_32(SYSCFG_BASE + SYSCFG_CMPENCLRR, SYSCFG_CMPENSETR_MPU_EN);
 
 	stm32mp1_clk_disable_non_secure(SYSCFG);
 }