egl/dri: fix error value with unknown drm format

According to the EGL_EXT_image_dma_buf_import spec, creating an EGL
image with a DRM format not supported should yield the BAD_MATCH
error :

"
       * If <target> is EGL_LINUX_DMA_BUF_EXT, and the EGL_LINUX_DRM_FOURCC_EXT
         attribute is set to a format not supported by the EGL, EGL_BAD_MATCH
         is generated.
"

Signed-off-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Fixes: 20de7f9f ("egl/dri2: support for creating images out of dma buffers")
Reviewed-by: Emil Velikov <emil.velikov@collabora.com>
Reviewed-by: Tapani Pälli <tapani.palli@intel.com>
Reviewed-by: Eric Engestrom <eric.engestrom@intel.com>
Reviewed-by: Chad Versace <chadversary@chromium.org>
(cherry picked from commit 1c56d211)