staging: vchiq_arm: Track bulk user data pointer separately

staging: vchiq_arm: Track bulk user data pointer separately

A bulk callback transfer can be initiated from two places -
inside kernel interface or from user interface. However,
the callback data pointer 'cb_data' is used for tracking both
sets of data pointer. This commit tracks the callback
data pointer from user interface (named as 'cb_userdata') separately,
in the bulk transfer service callback.

This is esentially done by adding a 'void __user *cb_userdata' for
tracking __user pointers in vchiq_bulk and vchiq_completion_data
structs. Furthermore, the 'cb_userdata' data pointer is appended to
the vchiq_service's callback signature.

Separating the two callback data pointers ('cb_data' and 'cb_userdata')
fixes the sparse warnings around mixing userspace and kernel space
pointers.

As there are no additional sparse warnings left for vc04_services,
drop the relevant entry from the TODO.

Signed-off-by: Umang Jain <umang.jain@ideasonboard.com>
Link: https://lore.kernel.org/r/20241023110406.885199-7-umang.jain@ideasonboard.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>