buildroot

packages: rename misc. occurrences of _OPT into _OPTS

To be consistent with the recent change of FOO_MAKE_OPT into FOO_MAKE_OPTS,
change remaining occurrences of _OPT into _OPTS.

Signed-off-by: Thomas De Schampheleire <thomas.de.schampheleire@gmail.com>
Reviewed-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>