core: backup: add STM32U5xx guard

Some serie still require to use their name due to wrong
LL API prototype using RTC parameter instead of TAMP.

Signed-off-by: Frederic Pillon <[email protected]>

Author: fpistm

cores/arduino/stm32/backup.h

@@ -106,7 +106,7 @@ static inline void setBackupRegister(uint32_t index, uint32_t value)
 #elif defined(RTC_BKP0R)
   LL_RTC_BAK_SetRegister(RTC, index, value);
 #elif defined(TAMP_BKP0R)
-#if defined(STM32G4xx) || defined(STM32L5xx) ||\
+#if defined(STM32G4xx) || defined(STM32L5xx) || defined(STM32U5xx) ||\
     defined(STM32MP1xx) || defined(STM32WLxx)
   /* For those series this API requires RTC even if it is not used
      and TAMP is used instead */
@@ -127,7 +127,7 @@ static inline uint32_t getBackupRegister(uint32_t index)
 #elif defined(RTC_BKP0R)
   return LL_RTC_BAK_GetRegister(RTC, index);
 #elif defined(TAMP_BKP0R)
-#if defined(STM32G4xx) || defined(STM32L5xx) ||\
+#if defined(STM32G4xx) || defined(STM32L5xx) || defined(STM32U5xx) ||\
     defined(STM32MP1xx) || defined(STM32WLxx)
   /* For those series this API requires RTC even if it is not used
      and TAMP is used instead */