gpu/drm: ingenic: Fix bogus crtc_atomic_check callback

The code was comparing the SoC's maximum height with the mode's width,
and vice-versa. D'oh.

Cc: stable@vger.kernel.org # v5.6
Fixes: a7c909b7

 ("gpu/drm: ingenic: Check for display size in CRTC atomic check")
Signed-off-by: Paul Cercueil <paul@crapouillou.net>
Link: https://patchwork.freedesktop.org/patch/msgid/20200516215057.392609-4-paul@crapouillou.net
Acked-by: Sam Ravnborg <sam@ravnborg.org>