OvmfPkg/LockBoxLib: list "LockBoxLib.h" in the INF files

OvmfPkg/LockBoxLib: list "LockBoxLib.h" in the INF files

Among other things, the header file declares the AllocateAcpiNvsPool()
function. This function is called from the "LockBoxLib.c" source file (in
the implementation of the SaveLockBox() library API), which is built into
both library instances. AllocateAcpiNvsPool() is implemented separately
per library instance, in "LockBoxBase.c" and "LockBoxDxe.c", respectively.

(In the LockBoxBaseLib instance, the AllocateAcpiNvsPool() function is
never expected to be called -- the public SaveLockBox() API should never
be called before the DXE phase --, we just have to provide a stub for
linking purposes.)

Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Jordan Justen <jordan.l.justen@intel.com>
Suggested-by: Michael Kinney <michael.d.kinney@intel.com>
Ref: http://mid.mail-archive.com/E92EE9817A31E24EB0585FDF735412F56327F7D3@ORSMSX113.amr.corp.intel.com
Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Reviewed-by: Jordan Justen <jordan.l.justen@intel.com>