build: Remove config.mk

Signed-off-by: Pawel Dziepak <pdziepak@quarnos.org>
build: Add default configuration

Signed-off-by: Pawel Dziepak <pdziepak@quarnos.org>
arch/x86_64: Update x86_64 code

Signed-off-by: Pawel Dziepak <pdziepak@quarnos.org>