media: staging: imx: Add ISI capture for imx8qm/imx8qxp

Because commit cc6562f5("media: staging: imx: add isi
capture driver support for imx8qm/qxp") mistakenly deleted
obj-$(CONFIG_IMX8_ISI_CORE) += imx8-capture.o, so this patch
will add it to ensure camera ISI capture normal use.

Signed-off-by: Xiaolei Wang <xiaolei.wang@windriver.com>
Signed-off-by: Bruce Ashfield <bruce.ashfield@gmail.com>