maliit-framework: Don't build the SDK

The SDK installs binaries in the /usr/share/doc directory

This fixes QA errors like:

ERROR: QA Issue: non debug package contains .debug directory:
maliit-framework-doc path
/work/armv7a-vfp-neon-oe-linux-gnueabi/maliit-framework/0.92.3+git1+750842dec74a9b17dca91ef779c4fc5a43c4d9dc-r0/packages-split/maliit-framework-doc/usr/share/doc/maliit-framework/maliit-sdk/examples/apps/settings/.debug/maliit-exampleapp-settings

Signed-off-by: Samuel Stirtzel <s.stirtzel@googlemail.com>
Signed-off-by: Martin Jansa <Martin.Jansa@gmail.com>