egl: simplify eglSwapInterval() fallback logic

Signed-off-by: Eric Engestrom <eric@engestrom.ch>
Reviewed-by: Emil Velikov <emil.velikov@collabora.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/6153>
diff --git a/src/egl/main/eglapi.c b/src/egl/main/eglapi.c
index e6ee31c..405be03 100644
--- a/src/egl/main/eglapi.c
+++ b/src/egl/main/eglapi.c
@@ -1287,15 +1287,10 @@
                     surf->Config->MinSwapInterval,
                     surf->Config->MaxSwapInterval);
 
-   if (surf->SwapInterval != interval) {
-      if (disp->Driver->SwapInterval)
-         ret = disp->Driver->SwapInterval(disp, surf, interval);
-      else
-         ret = EGL_TRUE;
-   }
-   else {
+   if (surf->SwapInterval != interval && disp->Driver->SwapInterval)
+      ret = disp->Driver->SwapInterval(disp, surf, interval);
+   else
       ret = EGL_TRUE;
-   }
 
    if (ret)
       surf->SwapInterval = interval;