support/dependencies: use the new kconfig option to check UTF8 locale

support/dependencies: use the new kconfig option to check UTF8 locale

Currently, we require a host with an UTF-8 locale as soone as we build a
Buildroot toolchain with support for locales. This means that we do
erquire such a locale when building a toolchain with either uClibc,
glibc or musl.

However, glibc and musl do not require such a locale to be present.

Use the new option to check if an UTF8 locale is needed on the host,
rather than deriving that from toolchain settings.

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