media: staging: media/atomisp: don't compile unused code

currently the functions defined in ibuf_ctrl_rmgr.c file are only
used by isys_init.c when CONFIG_VIDEO_ATOMISP_ISP2401 is selected
so dont't compile it when not needed, also fixes some sparse warnings

Link: https://lore.kernel.org/linux-media/YDEZu3oniT/vUMMY@karthik-strix-linux.karthek.comSigned-off-by: karthik alapati <mail@karthek.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

drivers/staging/media/atomisp/Makefile

@@ -126,7 +126,6 @@ atomisp-objs += \
 	pci/runtime/inputfifo/src/inputfifo.o \
 	pci/runtime/isp_param/src/isp_param.o \
 	pci/runtime/isys/src/csi_rx_rmgr.o \
-	pci/runtime/isys/src/ibuf_ctrl_rmgr.o \
 	pci/runtime/isys/src/isys_dma_rmgr.o \
 	pci/runtime/isys/src/isys_init.o \
 	pci/runtime/isys/src/isys_stream2mmio_rmgr.o \
@@ -323,7 +322,9 @@ DEFINES := -DHRT_HW -DHRT_ISP_CSS_CUSTOM_HOST -DHRT_USE_VIR_ADDRS -D__HOST__
 #DEFINES += -DUSE_KMEM_CACHE
 
 ifeq ($(CONFIG_VIDEO_ATOMISP_ISP2401),y)
-atomisp-objs += $(obj-cht)
+atomisp-objs += \
+	$(obj-cht) \
+	pci/runtime/isys/src/ibuf_ctrl_rmgr.o
 DEFINES += -DISP2401 -DISP2401_NEW_INPUT_SYSTEM -DSYSTEM_hive_isp_css_2401_system
 else
 atomisp-objs += $(obj-byt)