drm/msm/sde: move crtc caching to encoder_modeset

Atomic commit path calls encoder_modeset followed by
encoder_enable. Crtc caching within encoder_enable is late
for bootup cases because modeset request also need the
cached crtc access. Avoid invalid crtc error message
by caching at modeset level instead of encoder enable.

Change-Id: I1a9ba3e79a3ef6abee8fec7a7517ce32f1f88c93
Signed-off-by: Dhaval Patel <pdhaval@codeaurora.org>