media: platform: Change MTK_JPEG_COMP_MAX macro definition location

Move MTK_JPEG_COMP_MAX definition to mtk_jpeg_core.h file, because it
is used by mtk_jpeg_core.c file.

Reviewed-by: Tomasz Figa <tfiga@chromium.org>
Signed-off-by: Xia Jiang <xia.jiang@mediatek.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>