add features/gpio/mockup.scc to KERNEL_FEATURES when ptest
is enabled as it is required for testing libgpiod.
(From OE-Core rev: 906cde06bee319e788c76abb8f8295ed9921ccb1)
Signed-off-by: Sakib Sajal <sakib.sajal@windriver.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>