LinuxFramebuffer: Output: Drm: Add drmModeAddFB2 wrapper

drmModeAddFB2 gives us the possibility to specify the pixel format
directly in the call

Signed-off-by: Matheus Castello <matheus@castello.eng.br>

src/Linux/Avalonia.LinuxFramebuffer/Output/Drm.cs

@@ -176,7 +176,13 @@ namespace Avalonia.LinuxFramebuffer.Output
         [DllImport(libdrm, SetLastError = true)]
         public static extern int drmModeAddFB(int fd, uint width, uint height, byte depth,
             byte bpp, uint pitch, uint bo_handle,
-            out uint buf_id); 
+            out uint buf_id);
+
+        [DllImport(libdrm, SetLastError = true)]
+        public static extern int drmModeAddFB2(int fd, uint width, uint height,
+            uint pixel_format, uint[] bo_handles, uint[] pitches,
+            uint[] offsets, out uint buf_id, uint flags);
+
         [DllImport(libdrm, SetLastError = true)]
         public static extern int drmModeSetCrtc(int fd, uint crtcId, uint bufferId,
             uint x, uint y, uint *connectors, int count,
@@ -278,7 +284,7 @@ namespace Avalonia.LinuxFramebuffer.Output
         }
         
         [DllImport(libgbm, SetLastError = true)]
-        public static extern ulong gbm_bo_get_handle(IntPtr bo);
+        public static extern GbmBoHandle gbm_bo_get_handle(IntPtr bo);
 
         public static  class GbmColorFormats
         {