feat(stm32mp1): disable MMU earlier when going to standby

The disabling of MMU before entering standby mode is no more done in
stm32_pwr_down_wfi_wrapper(). It has to be done by BL32. This is OK for
OP-TEE, but it was not the case for SP_MIN. The call to the function
disable_mmu_icache_secure() is then done before stm32_pwr_down_wfi()
in stm32_pwr_domain_pwr_down_wfi().

Signed-off-by: Yann Gautier <yann.gautier@foss.st.com>
Change-Id: I31ea5b38e98e381069573aee646debe90a2935dc
Reviewed-on: https://gerrit.st.com/c/mpu/oe/st/tf-a/+/315669
ACI: CITOOLS <MDG-smet-aci-reviews@list.st.com>
ACI: CIBUILD <MDG-smet-aci-builds@list.st.com>
Domain-Review: Patrick DELAUNAY <patrick.delaunay@foss.st.com>

Author: Yann-lms

plat/st/stm32mp1/stm32mp1_pm.c

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2015-2021, ARM Limited and Contributors. All rights reserved.
+ * Copyright (c) 2015-2023, ARM Limited and Contributors. All rights reserved.
  *
  * SPDX-License-Identifier: BSD-3-Clause
  */
@@ -169,13 +169,13 @@ static void __dead2 stm32_pwr_domain_pwr_down_wfi(const psci_power_state_t
 		void (*warm_entrypoint)(void) =
 			(void (*)(void))stm32_sec_entrypoint;
 
+		disable_mmu_icache_secure();
+
 		stm32_pwr_down_wfi(stm32_is_cstop_done(),
 				   stm32mp1_get_lp_soc_mode(PSCI_MODE_SYSTEM_SUSPEND));
 
 		stm32_exit_cstop();
 
-		disable_mmu_icache_secure();
-
 		warm_entrypoint();
 	}