#509 STM32L1 Medium Density Plus RTC Subseconds

[wild-boar]

This patch (against stable_2.6.x) allowed me to add subseconds to the RTC driver for a STM32L1 MDP device:

Index: os/hal/platforms/STM32L1xx/stm32_registry.h
===================================================================
--- os/hal/platforms/STM32L1xx/stm32_registry.h (revision 6970)
+++ os/hal/platforms/STM32L1xx/stm32_registry.h (working copy)
@@ -89,7 +89,11 @@

 /* RTC attributes.*/
 #define STM32_HAS_RTC                       TRUE
+#if defined(STM32L1XX_MDP)
+#define STM32_RTC_HAS_SUBSECONDS            TRUE
+#else
 #define STM32_RTC_HAS_SUBSECONDS            FALSE
+#endif
 #define STM32_RTC_IS_CALENDAR               TRUE