Revert "Linktype check for native:product"

This reverts commit 4e7e76fe.

Reason for revert: build breaks (bid: 6147225) and postsubmit test fails.
There are some modules that have both "product_specific: true" and "vendor_available: true", which tags the module as "native:product" unintentionally.
We need to clean up these cases first and revisit this CL.

Bug: 146620523
Bug: 147987741
Change-Id: Ib07543235d72a135b6b732aaa909c147d2df832b