Fix -Wundef warnings due to use of unguarded SDL_JOYSTICK_VITA

src/joystick/SDL_gamepad_db.h

@@ -1001,7 +1001,7 @@ static const char *s_GamepadMappings[] = {
 #ifdef SDL_JOYSTICK_PSP
     "00000000505350206275696c74696e00,PSP builtin joypad,crc:bb86,a:b2,b:b1,back:b10,dpdown:b6,dpleft:b7,dpright:b9,dpup:b8,leftshoulder:b4,leftx:a0,lefty:a1,rightshoulder:b5,rightx:a2,righty:a3,start:b11,x:b3,y:b0,",
 #endif
-#if SDL_JOYSTICK_VITA
+#ifdef SDL_JOYSTICK_VITA
     "0000000050535669746120436f6e7400,PSVita Controller,crc:d598,a:b2,b:b1,back:b10,dpdown:b6,dpleft:b7,dpright:b9,dpup:b8,leftshoulder:b4,leftstick:b14,lefttrigger:a4,leftx:a0,lefty:a1,rightshoulder:b5,rightstick:b15,righttrigger:a5,rightx:a2,righty:a3,start:b11,x:b3,y:b0,",
 #endif
 #if SDL_JOYSTICK_N3DS

src/joystick/vita/SDL_sysjoystick.c

@@ -20,7 +20,7 @@
 */
 #include "SDL_internal.h"
 
-#if SDL_JOYSTICK_VITA
+#ifdef SDL_JOYSTICK_VITA
 
 /* This is the PSVita implementation of the SDL joystick API */
 #include <psp2/types.h>