tools/fiptool: Add Makefile.msvc to build on Windows.

This change adds nmake compatible Makefile.msvc file for
building (nmake /FMakefile.msvc) fiptool on the Windows.

Change-Id: Iccd1fe8da072edd09eb04b8622f27b3c4693b281
Signed-off-by: Girish Pathak <girish.pathak@arm.com>