package/pkg-cmake.mk: add ccache support for host packages

This ccache support for host-cmake-package uses the same logic as the
one done for the target packages in the toolchainfile.cmake file.

[Thomas: fix lots of mistakes.]

Signed-off-by: Samuel Martin <s.martin49@gmail.com>
Cc: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>