wgbm: Don't destroy a surface if init fails
Otherwise, we segfault trying to look up the platform from a window that was never properly initialized.
Fixes: 6695ab42 ("gbm: factor out gbm_window_{init,teardown}")
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Otherwise, we segfault trying to look up the platform from a window that was never properly initialized.
Fixes: 6695ab42 ("gbm: factor out gbm_window_{init,teardown}")