cmd/internal/obj/ppc64: remove stackbarrier function check
cmd/internal/obj/ppc64: remove stackbarrier function check

Stack barriers were removed in CL 36620.

Change-Id: If124d65a73a7b344a42be2a4b386a14d7a0a428b
Reviewed-on: https://go-review.googlesource.com/38169
Reviewed-by: Michael Hudson-Doyle <5e87ffb38a52af6fb9a19b679e9122c7a4d601a5@canonical.com>
Reviewed-by: David Chase <ae171625adc8645b8b79b7e405a6da5aba5341e0@google.com>

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