When setting crtc->gamma_size to randr_crtc->gammaSize we should
use randr_crtc->gammaSize to allocate new gamma table in crtc.
Currently, if randr_crtc->gammaSize > crtc->gammaSize the subsequent
memcpy will overwrite memory beyond the end of gamma table.
Signed-off-by: Dominik Behr <dbehr@chromium.org>
Reviewed-by: Stéphane Marchesin <marcheu@chromium.org>
Signed-off-by: Keith Packard <keithp@keithp.com>