[media] Add missing help for some menuconfig items

Help was missing during some items reorganization. Add them.

Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
diff --git a/drivers/media/pci/Kconfig b/drivers/media/pci/Kconfig
index 083b62f..d4e2ed3 100644
--- a/drivers/media/pci/Kconfig
+++ b/drivers/media/pci/Kconfig
@@ -1,6 +1,9 @@
 menuconfig MEDIA_PCI_SUPPORT
 	bool "Media PCI Adapters"
 	depends on PCI && MEDIA_SUPPORT
+	help
+	  Enable media drivers for PCI/PCIe bus.
+	  If you have such devices, say Y.
 
 if MEDIA_PCI_SUPPORT