drivers: Makefile: Add rule to compile video driver

Compile video driver at SPL using CONFIG_SPL_VIDEO.

Signed-off-by: Nikhil M Jain <n-jain1@ti.com>
Reviewed-by: Devarsh Thakkar <devarsht@ti.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
Tested-by: Simon Glass <sjg@chromium.org>  # qemu-x86_64
diff --git a/drivers/Makefile b/drivers/Makefile
index 58be410..928a8b0 100644
--- a/drivers/Makefile
+++ b/drivers/Makefile
@@ -61,6 +61,7 @@
 obj-$(CONFIG_SPL_SATA) += ata/ scsi/
 obj-$(CONFIG_SPL_LEGACY_BLOCK) += block/
 obj-$(CONFIG_SPL_THERMAL) += thermal/
+obj-$(CONFIG_SPL_VIDEO) +=video/
 
 endif
 endif