platform: stm: bl2: log set_wmsec2 on bank 2 mismatch

The 'else if' branch handling the case where bank 2 must be fully
non-secure was missing the BOOT_LOG_ERR("... : set wmsec2") message
present in all other protection-mismatch branches of
low_level_security.c.

Align the log output with the rest of the function. No functional
change.

Change-Id: If645f440809a389e78825ac054405e636768394a
Signed-off-by: Benjamin Grolleau <benjamin.grolleau@outlook.com>

Author: Grolleau-Benjamin

platform/ext/target/stm/common/stm32u5xx/bl2/low_level_security.c

@@ -712,6 +712,7 @@ void LL_SECU_CheckStaticProtections(void)
     BOOT_LOG_ERR("Unexpected value for secure flash protection");
     Error_Handler();
 #else
+    BOOT_LOG_ERR("Unexpected value for secure flash protection : set wmsec2");
     /* bank is not unsecured , modify option bytes */
     flash_option_bytes_bank2.WMSecStartPage = 127;
     flash_option_bytes_bank2.WMSecEndPage = 0;