platform: rename debug IO abstraction
generate Kconfig entry at build time

file mk/Config.in is no longer required because we can always generate
during build time. Also, the dependency of Kconfig files is improved.
mk: enable interpretation of backslash escapes

Signed-off-by: Viller Hsiao <villerhsiao@gmail.com>
mk: remove obsolete config variables

The config variables are generated automatically by including .config

Signed-off-by: Viller Hsiao <villerhsiao@gmail.com>
Merge pull request #52 from vh21/master

mk: enable interpretation of backslash escapes
simplify the usage of init-hook: no additional name required