Marvell/Library: Introduce common header for the SMC ID's

Marvell firmware allows to use SiP services other than
for ComPhy handling. In order to avoid spreading the SMC
ID's definitions across many files, introduce common header
for that purpose.

Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Marcin Wojtas <mw@semihalf.com>
Reviewed-by: Leif Lindholm <leif.lindholm@linaro.org>