devel/libccid: Fix Meson options so contrib tools are built

The port was incorrectly using non-existent MESON_TRUE/MESON_FALSE
helpers. As a result, -Denable-extras was never passed to Meson, and
the contrib utilities (Kobil_mIDentity_switch, RSA_SecurID_getpasswd)
were not built, causing post-install to fail.

Switch to explicitly setting MESON_ARGS to control build options. This
restores building of contrib programs and fixes the build.

Approved by: portmgr (just-fix-it)
Fixes: 60038512eb (devel/libccid: Update to 1.6.2)
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D52391