egl: Fix uninitialized variable warning
Fedora's gcc 12.2.1 says:
../src/egl/main/eglapi.c: In function ‘eglDupNativeFenceFDANDROID’:
../src/egl/main/eglapi.c:2268:11: warning: ‘ret’ may be used uninitialized [-Wmaybe-uninitialized]
2268 | EGLint ret;