gpu: ipu-v3 ipu-cpmem: Remove unused functions

gpu: ipu-v3 ipu-cpmem: Remove unused functions

ipu_cpmem_set_yuv_interleaved() was added in 2012 by
commit 0125f21b2baf ("staging: drm/imx: Add
ipu_cpmem_set_yuv_interleaved()")
but has remained unused.

ipu_cpmem_get_burstsize() was added in 2016 by
commit 03085911d7bb ("gpu: ipu-cpmem: Add ipu_cpmem_get_burstsize()")
but has remained unused.

Remove them.

Signed-off-by: Dr. David Alan Gilbert <linux@treblig.org>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20241226022752.219399-8-linux@treblig.org
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>