style: fix some of the easier style bugs

No real changes.

lib/stm32/l4/flash.c

@@ -246,7 +246,7 @@ void flash_lock_option_bytes(void)
  * This performs all operations necessary to program a 32 bit word to FLASH
  * memory. The program error flag should be checked separately for the event
  * that memory was not properly erased.
- * 
+ *
  * @param[in] address Starting address in Flash.
  * @param[in] data word to write
  */
@@ -340,4 +340,5 @@ void flash_program_option_bytes(uint32_t data)
 	FLASH_OPTR |= FLASH_CR_OPTSTRT;
 	flash_wait_for_last_operation();
 }
-/**@}*/
+/**@}*/
+