cmd/link: directly get max pc value in findfunctab
cmd/link: directly get max pc value in findfunctab

Change-Id: I70afd2f7b6783926174c4e66565b711cffeb97c5
Reviewed-on: https://go-review.googlesource.com/c/150141
Run-TryBot: Ian Lance Taylor <87e9c6d529889242b7e184afb632328636553ab4@golang.org>
TryBot-Result: Gobot Gobot <66cb808b70d30c07676d5e946fee83fd561249e5@golang.org>
Reviewed-by: Ian Lance Taylor <87e9c6d529889242b7e184afb632328636553ab4@golang.org>

golang/go,cloudflare/go,josharian/go,CAFxX/go,CAFxX/go,golang/go,josharian/go,CAFxX/go,akutz/go,cloudflare/go,CAFxX/go,golang/go,josharian/go,golang/go,josharian/go,akutz/go,cloudflare/go,nawawi/go,cloudflare/go,josharian/go,nawawi/go,CAFxX/go,nawawi/go,golang/go,golang/go,CAFxX/go,nawawi/go,golang/go,cloudflare/go,nawawi/go,josharian/go,josharian/go,nawawi/go,josharian/go,nawawi/go,akutz/go,CAFxX/go,akutz/go,cloudflare/go,cloudflare/go,nawawi/go,CAFxX/go,akutz/go,cloudflare/go,akutz/go,akutz/go,golang/go,akutz/go