nativesdk-qtbase: fix packaging QA issue

nativesdk-qtbase_git.bb had a line removed in meta-qt5 commit
"3224b02 nativesdk-qtbase: use default PACKAGES" that causes following error:

   ERROR: nativesdk-qtbase-5.11.2+gitAUTOINC+b0dce506cc-r0 do_package: QA Issue: nativesdk-qtbase:
   Files/directories were installed but not shipped in any package:
   /opt/poky/2.3.4/sysroots/x86_64-pokysdk-linux/usr/share
   /opt/poky/2.3.4/sysroots/x86_64-pokysdk-linux/usr/share/cmake
   /opt/poky/2.3.4/sysroots/x86_64-pokysdk-linux/usr/share/cmake/OEToolchainConfig.cmake.d
   /opt/poky/2.3.4/sysroots/x86_64-pokysdk-linux/usr/share/cmake/OEToolchainConfig.cmake.d/OEQt5Toolchain.cmake

Moved fix from meta-qt5 to meta-boot2qt to reduce delta between meta-qt5 and upstream.

Change-Id: I452a10db11aa63e42104d159d810fee5b407dda1
Reviewed-by: Samuli Piippo <samuli.piippo@qt.io>