egl/wayland: Ignore invalid modifiers

egl/wayland: Ignore invalid modifiers

If the underlying driver does not support modifiers, dmabuf will still
advertise formats through the 'modifier' event, but send them with an
invalid modifier. Ignore them if this is the case, rather than passing
them through to the driver.

Signed-off-by: Daniel Stone <daniels@collabora.com>
Reviewed-by: Emil Velikov <emil.velikov@collabora.com>
Fixes: 02cc35937277 ("egl/wayland: Use linux-dmabuf interface for buffers")