SPM: Clean up SPM log output

Couple of things for cleaning up the SPM log:

* As 'MSGVAL' is customized for 'message + value', append '\r\n' at
  the end to save extra 'MSG("\r\n")' which looks redundant.
  Also adjusted related caller place to provide better adaptation.

* Override the default log level into Debug(3) under debug build.

Change-Id: If4392262fd112494ec86741c1ba5c8f256fd79fe
Signed-off-by: Ken Liu <Ken.Liu@arm.com>
7 files changed