chore(u3): backup register support

Signed-off-by: Frederic Pillon <frederic.pillon@st.com>

Author: fpistm

libraries/SrcWrapper/inc/backup.h

@@ -121,8 +121,8 @@ static inline void setBackupRegister(uint32_t index, uint32_t value)
   LL_RTC_BAK_SetRegister(RTC, index, value);
 #elif defined(TAMP_BKP0R)
 #if defined(STM32G4xx) || defined(STM32H5xx) || defined(STM32L5xx) ||\
-    defined(STM32U5xx) || defined(STM32MP1xx) || defined(STM32WBAxx) ||\
-    defined(STM32WLxx)
+    defined(STM32U3xx) || defined(STM32U5xx) || defined(STM32MP1xx) || \
+    defined(STM32WBAxx) || defined(STM32WLxx)
   /* For those series this API requires RTC even if it is not used
      and TAMP is used instead */
   LL_RTC_BKP_SetRegister(RTC, index, value);
@@ -145,8 +145,8 @@ static inline uint32_t getBackupRegister(uint32_t index)
   return LL_RTC_BAK_GetRegister(RTC, index);
 #elif defined(TAMP_BKP0R)
 #if defined(STM32G4xx) || defined(STM32H5xx) || defined(STM32L5xx) ||\
-    defined(STM32U5xx) || defined(STM32MP1xx) || defined(STM32WBAxx) ||\
-    defined(STM32WLxx)
+    defined(STM32U3xx) || defined(STM32U5xx) || defined(STM32MP1xx) || \
+    defined(STM32WBAxx) || defined(STM32WLxx)
   /* For those series this API requires RTC even if it is not used
      and TAMP is used instead */
   return LL_RTC_BKP_GetRegister(RTC, index);