pkgconfig: Add pkg-config-native to SDK

pkgconfig: Add pkg-config-native to SDK

Building weston with an SDK fails to find pkg-config-native:
```
Did not find pkg-config by name 'pkg-config-native'
Found pkg-config: NO
Found CMake: /opt/poky/5.1/sysroots/x86_64-pokysdk-linux/usr/bin/cmake (3.31.0)
Build-time dependency wayland-scanner found: NO (tried cmake)

protocol/meson.build:1:14: ERROR: Dependency lookup for wayland-scanner with method 'pkgconfig' failed: Pkg-config for machine build machine not found. Giving up.
```

Fix the problem by extending the pkg-config-native wrapper install to
class-nativesdk.

Signed-off-by: Tom Hochstein <tom.hochstein@oss.nxp.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>