drm/ast: vga: Inline ast_vga_connector_init()

Inline ast_vga_connector_init() into its only caller. The helper
currently only does half of the connector-init work and is trivial
enough to be inlined. While at it, remove the error message from the
call to ast_ddc_create(). The function already warns on errors.

Also set the local variables for encoder and connector as late as
possible, so that the compiler warns if we use them before having
initialized the instance.

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Jocelyn Falempe <jfalempe@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240911115347.899148-9-tzimmermann@suse.de