staging: vchiq_arm: introduce free_bulk_waiter

Avoid the copy & paste of freeing the bulk waiter and move it into a
separate function. Found by CPD.

Signed-off-by: Stefan Wahren <stefan.wahren@i2se.com>
Link: https://lore.kernel.org/r/1622735405-9980-3-git-send-email-stefan.wahren@i2se.com


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>