Convert .PHONY target of `checkapi ` to Android.bp

Since Soong has been able to correctly add dependencies to .PHONY
targets since aosp/2884366, it is now possible to directly use
`phony_deps` to add the genrules used by `checkapi` to its dependencies
and convert them to Android.bp.

Bug: 309730110
Test: m checkapi
Change-Id: Ideb9f647415423a5864d221b85442b995ac67906