cmd/link: remove some unnecessary comments
cmd/link: remove some unnecessary comments

The comments about pcln functions are obsolete since those functions
now live in cmd/internal/obj. The copyright header is redundant with
the existing one at the top of the file.

Change-Id: I568fd3d259253a0d8eb3b0a157d008df1b5de106
Reviewed-on: https://go-review.googlesource.com/31315
Reviewed-by: Ian Lance Taylor <87e9c6d529889242b7e184afb632328636553ab4@golang.org>

vsekhar/elastic-go,codestation/go,momchil-velikov/go,ImJasonH/go,linux-on-ibm-z/go,momchil-velikov/go,suncycheng/go,Cofyc/go,cloudflare/go,vsekhar/elastic-go,christopher-henderson/Go,ImJasonH/go,CAFxX/go,codestation/go,linux-on-ibm-z/go,Cofyc/go,CAFxX/go,CAFxX/go,cloudflare/go,Cofyc/go,goodlang/good,vsekhar/elastic-go,josharian/go,cloudflare/go,nawawi/go,linux-on-ibm-z/go,josharian/go,linux-on-ibm-z/go,cloudflare/go,nawawi/go,ImJasonH/go,vsekhar/elastic-go,nawawi/go,josharian/go,akutz/go,codestation/go,josharian/go,cloudflare/go,derekmarcotte/go,nawawi/go,goodlang/good,momchil-velikov/go,codestation/go,derekmarcotte/go,suncycheng/go,golang/go,polyverse-security/go,derekmarcotte/go,Cofyc/go,derekmarcotte/go,polyverse-security/go,akutz/go,derekmarcotte/go,nawawi/go,CAFxX/go,josharian/go,cloudflare/go,Cofyc/go,goodlang/good,vsekhar/elastic-go,suncycheng/go,momchil-velikov/go,suncycheng/go,momchil-velikov/go,josharian/go,polyverse-security/go,codestation/go,golang/go,Cofyc/go,suncycheng/go,CAFxX/go,akutz/go,nawawi/go,ImJasonH/go,ImJasonH/go,nawawi/go,ImJasonH/go,akutz/go,suncycheng/go,polyverse-security/go,golang/go,golang/go,CAFxX/go,goodlang/good,derekmarcotte/go,suncycheng/go,derekmarcotte/go,momchil-velikov/go,goodlang/good,polyverse-security/go,codestation/go,josharian/go,derekmarcotte/go,momchil-velikov/go,linux-on-ibm-z/go,Cofyc/go,vsekhar/elastic-go,CAFxX/go,golang/go,ImJasonH/go,akutz/go,codestation/go,CAFxX/go,akutz/go,goodlang/good,goodlang/good,codestation/go,nawawi/go,josharian/go,goodlang/good,vsekhar/elastic-go,linux-on-ibm-z/go,cloudflare/go,linux-on-ibm-z/go,suncycheng/go,vsekhar/elastic-go,Cofyc/go,golang/go,golang/go,polyverse-security/go,ImJasonH/go,akutz/go,golang/go,linux-on-ibm-z/go,cloudflare/go,akutz/go,polyverse-security/go,momchil-velikov/go,polyverse-security/go