OvmfPkg/PlatformPei: list "Platform.h" in the INF file
OvmfPkg/PlatformPei: list "Platform.h" in the INF file

The header file declares several functions and global variables that are
shared between various translation units in this module.

Cc: Anthony Perard <bd4ca9e282b840f7a66451c0c1b8fcfed96ac883@citrix.com>
Cc: Ard Biesheuvel <66d3c5fdaeea7ff1f996ad04f2c45e08ab38e2f5@linaro.org>
Cc: Jordan Justen <a79006884ba9cf5f4f7fcbb92a15b208780d8c97@intel.com>
Cc: Julien Grall <2fe41d4e32b0bb991f63b975f2bed08c1e666665@linaro.org>
Suggested-by: Michael Kinney <fd20bc543a9f65bb633fac7d08a403c1f1c8eb6c@intel.com>
Ref: eceeacc5b443184c66bbe56b32167659412ebeee@ORSMSX113.amr.corp.intel.com
Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Laszlo Ersek <7437296077edea1cb64451c122c4dac071f0cfbc@redhat.com>
Reviewed-by: Ard Biesheuvel <66d3c5fdaeea7ff1f996ad04f2c45e08ab38e2f5@linaro.org>
Reviewed-by: Jordan Justen <a79006884ba9cf5f4f7fcbb92a15b208780d8c97@intel.com>

MattDevo/edk2,MattDevo/edk2,MattDevo/edk2,MattDevo/edk2,MattDevo/edk2,MattDevo/edk2,MattDevo/edk2,MattDevo/edk2