egl: fix error string for dri2_create_image_dma_buf()

egl: fix error string for dri2_create_image_dma_buf()

Using dri2_create_image_khr_texture_error() here prints an error
like so:

    command: eglCreateImageKHR, error: EGL_BAD_ALLOC (0x3003), message: "dri2_create_image_khr_texture"

This is confusing, because dri2_create_image_khr_texture() is
unrelated to this error.

Instead, print a more accurate error manually.

Signed-off-by: Simon Ser <contact@emersion.fr>
Reviewed-by: Eric Engestrom <eric@igalia.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/19156>