meson: correct bindgen_clang_argments

meson: correct bindgen_clang_argments

Follow the changes in Clang search paths and specify sysroot via the
TOOLCHAIN_OPTIONS, otherwise clang will fail to find system headers when
executed by bindgen.

For SDK packages TOOLCHAIN_OPTIONS don't contain full sysroot path, so
specify the correct directory explicitly.

Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>
Signed-off-by: Khem Raj <raj.khem@gmail.com>
Signed-off-by: Mathieu Dubois-Briand <mathieu.dubois-briand@bootlin.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>