apply-patches.sh: Use the "APPLY_PATCHES" variable to call the script

To easy up adding optional parameters when calling the
"apply-patches.sh" add and use the "APPLY_PATCHES" variable to execute
the script.

Signed-off-by: Fabio Porcedda <fabio.porcedda@gmail.com>
Reviewed-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>