zink: store drm format as internal_format for imported resources

zink: store drm format as internal_format for imported resources

internal_format is the "real" format of a resource, and the "real" format
of imported resources is the external-facing format, not the pipe format

this ensures the correct format is available for internal ops, such as nplanes queries

Fixes: 2e2775c11b0 ("zink: fix PIPE_RESOURCE_PARAM_NPLANES with format modifier")
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/20753>
(cherry picked from commit 072e29a22e2cd3c738a3bee463f6aebd40159966)