SAML21J18A: #endif without #if in analogout_api.c

This PR: 3bd3aca6db (diff-995cd6fe18f4fabfb549266dde0a3784) broke the SAML21J18A target, as there was no `#if DEVICE_ANALOGOUT` call, and this PR added an `#endif` there that's not matched now.

targets/TARGET_Atmel/TARGET_SAM_CortexM0P/TARGET_SAML21J18A/analogout_api.c

@@ -21,6 +21,8 @@
 #include "PeripheralPins.h"
 #include "dac.h"
 
+#if DEVICE_ANALOGOUT
+
 extern uint8_t g_sys_init;
 
 #define MAX_VAL_12BIT 0x0FFF  /*12 Bit DAC for SAML21*/
@@ -119,4 +121,5 @@ const PinMap *analogout_pinmap()
 {
     return PinMap_DAC;
 }
-#endif
+
+#endif // DEVICE_ANALOGOUT