staging: vchiq: Add details to Kconfig help texts

Add some details to the Kconfig definitions of $CONFIG_VCHIQ_CDEV and
$CONFIG_BCM2835_VCHIQ to help make the motive behind the configs a bit
more clear.

Reviewed-by: Stefan Wahren <[e-mail]>
Signed-off-by: Ojaswin Mujoo <[e-mail]>
Link: https://lore.kernel.org/r/a[e-mail]
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

drivers/staging/vc04_services/Kconfig

···
 	tristate "BCM2835 VCHIQ"
 	imply VCHIQ_CDEV
 	help
-		Kernel to VideoCore communication interface for the
-		BCM2835 family of products.
-		Defaults to Y when the Broadcom Videocore services
-		are included in the build, N otherwise.
+		Broadcom BCM2835 and similar SoCs have a VPU called VideoCore. This config
+		enables the VCHIQ driver, which implements a messaging interface between
+		the kernel and the firmware running on VideoCore. Other drivers use this
+		interface to communicate to the VPU. More specifically, the VCHIQ driver is
+		used by audio/video and camera drivers as well as for implementing MMAL
+		API, which is in turn used by several multimedia services on the BCM2835
+		family of SoCs.
+		Defaults to Y when the Broadcom Videocore services are included in
+		the build, N otherwise.
 
 if BCM2835_VCHIQ
 
 config VCHIQ_CDEV
 	bool "VCHIQ Character Driver"
 	help
-		Enable the creation of VCHIQ character driver to help
-		communicate with the Videocore platform.
+		Enable the creation of VCHIQ character driver. The cdev exposes ioctls used
+		by userspace libraries and testing tools to interact with VideoCore, via
+		the VCHIQ core driver (Check BCM2835_VCHIQ for more info).
+		This can be set to 'N' if the VideoCore communication is not needed by
+		userspace but only by other kernel modules (like bcm2835-audio).  If not
+		sure, set this to 'Y'.
 
 endif