README.rst: add build notes for Yocto, more to come...
README.rst: add build notes for Yocto, more to come...

Signed-off-by: Steve Arnold <fe6214edba4d9b2d20a723cfd9bdf269f8b2c023@gmail.com>

VCTLabs/DE1_SOC_Linux_FB,VCTLabs/DE1_SOC_Linux_FB,VCTLabs/DE1_SOC_Linux_FB,VCTLabs/DE1_SOC_Linux_FB