kcov, usbip: collect coverage from vhci_rx_loop

kcov, usbip: collect coverage from vhci_rx_loop

Add kcov_remote_start()/kcov_remote_stop() annotations to the
vhci_rx_loop() function, which is responsible for parsing USB/IP packets
coming into USB/IP client.

Since vhci_rx_loop() threads are spawned per vhci_hcd device instance, the
common kcov handle is used for kcov_remote_start()/stop() annotations
(see Documentation/dev-tools/kcov.rst for details). As the result kcov
can now be used to collect coverage from vhci_rx_loop() threads.

Co-developed-by: Andrey Konovalov <andreyknvl@google.com>
Acked-by: Shuah Khan <skhan@linuxfoundation.org>
Signed-off-by: Nazime Hande Harputluoglu <handeharputlu@google.com>
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Link: https://lore.kernel.org/r/f8114050f8d65aa0bc801318b1db532d9f432447.1606175386.git.andreyknvl@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>