build/core: Include linaro_compilerchecks.mk

Include linaro_compilerchecks.mk in core/config.mk to allow the macros
to be used in board configs

Change-Id: I3a0dfd0a3a1c09961e43ef8c2f3cbe50b8c00e20
Signed-off-by: Bernhard Rosenkraenzer <Bernhard.Rosenkranzer@linaro.org>
Signed-off-by: anerik <anerikgames@gmail.com>

Conflicts:
	core/config.mk