Use default fallback when generating cc deps

The current logic enforces a device arch match and omits a module
altogether if none is found. To collect a more comprehensive list
of cc deps for IDE (ASfP) project setup, we introduce a fallback
that defaults to an arbitrary (first-processed) variant.

Bug: 322369312
Test: refreshmod
Change-Id: Ic5e1fd39e569735ff90b5c71ab1395632cca9af7