Fix duplicate variations when using the VSDK.

When using the VSDK there can be multiple variations of the same module
for core, product, vendor, recovery. If two or more of those variations
exist, a suffix must be added to the variation to avoid duplicate modules
with the same name.

Bug: 188717568
Test: m -j nothing
Change-Id: Ifd8fa5590a8e225a97c2a8e3110d5d5f20beb50d