mk/config.mk.in: drop unused CONF_CC_OPTS for ia64
mk/config.mk.in: drop unused CONF_CC_OPTS for ia64

There is CONF_CC_OPTS_STAGE$(N) but not CONF_CC_OPTS
thus option does not work for a while.

Signed-off-by: Sergei Trofimovich <df7d2cee2e7ececeb2368216a0f9d0537fd32149@google.com>

nushio3/ghc,sdiehl/ghc,vikraman/ghc,nushio3/ghc,vikraman/ghc,shlevy/ghc,sgillespie/ghc,sdiehl/ghc,tjakway/ghcjvm,oldmanmike/ghc,vikraman/ghc,oldmanmike/ghc,vTurbine/ghc,snoyberg/ghc,tjakway/ghcjvm,vTurbine/ghc,ezyang/ghc,tjakway/ghcjvm,mcschroeder/ghc,vikraman/ghc,mcschroeder/ghc,vikraman/ghc,sgillespie/ghc,shlevy/ghc,nushio3/ghc,gridaphobe/ghc,mettekou/ghc,ezyang/ghc,gridaphobe/ghc,vTurbine/ghc,olsner/ghc,ezyang/ghc,gridaphobe/ghc,vTurbine/ghc,mcschroeder/ghc,mcschroeder/ghc,sgillespie/ghc,snoyberg/ghc,olsner/ghc,mettekou/ghc,vikraman/ghc,olsner/ghc,sgillespie/ghc,olsner/ghc,nushio3/ghc,mcschroeder/ghc,gridaphobe/ghc,vikraman/ghc,mettekou/ghc,sdiehl/ghc,mcschroeder/ghc,oldmanmike/ghc,sdiehl/ghc,mettekou/ghc,shlevy/ghc,shlevy/ghc,sgillespie/ghc,sdiehl/ghc,sdiehl/ghc,sgillespie/ghc,tjakway/ghcjvm,oldmanmike/ghc,mcschroeder/ghc,sdiehl/ghc,shlevy/ghc,gridaphobe/ghc,oldmanmike/ghc,oldmanmike/ghc,mettekou/ghc,snoyberg/ghc,oldmanmike/ghc,nushio3/ghc,tjakway/ghcjvm,shlevy/ghc,shlevy/ghc,olsner/ghc,mettekou/ghc,vTurbine/ghc,snoyberg/ghc,ezyang/ghc,gridaphobe/ghc,ezyang/ghc,snoyberg/ghc,vTurbine/ghc,gridaphobe/ghc,vTurbine/ghc,nushio3/ghc,tjakway/ghcjvm,snoyberg/ghc,tjakway/ghcjvm,olsner/ghc,nushio3/ghc,ezyang/ghc,ezyang/ghc,sgillespie/ghc,olsner/ghc,mettekou/ghc,snoyberg/ghc