SimObject: make get_config_as_dict() tolerate undefined params
SimObject: make get_config_as_dict() tolerate undefined params

Without this patch, undefined params cause a cryptic KeyError
in multidict inside get_config_as_dict().  This patch lets
undefined params through get_config_as_dict() so they can
once again generate meaningful error messages later on in
the configuration process.

rjschof/gem5,Weil0ng/gem5,HwisooSo/gemV-update,TUD-OS/gem5-dtu,briancoutinho0905/2dsampling,markoshorro/gem5,aclifton/cpeg853-gem5,markoshorro/gem5,qizenguf/MLC-STT,samueldotj/TeeRISC-Simulator,powerjg/gem5-ci-test,samueldotj/TeeRISC-Simulator,Weil0ng/gem5,qizenguf/MLC-STT,joerocklin/gem5,powerjg/gem5-ci-test,cancro7/gem5,TUD-OS/gem5-dtu,zlfben/gem5,markoshorro/gem5,cancro7/gem5,Weil0ng/gem5,powerjg/gem5-ci-test,gem5/gem5,joerocklin/gem5,KuroeKurose/gem5,SanchayanMaity/gem5,markoshorro/gem5,rjschof/gem5,kaiyuanl/gem5,austinharris/gem5-riscv,samueldotj/TeeRISC-Simulator,zlfben/gem5,rallylee/gem5,rallylee/gem5,kaiyuanl/gem5,yb-kim/gemV,briancoutinho0905/2dsampling,SanchayanMaity/gem5,briancoutinho0905/2dsampling,rallylee/gem5,cancro7/gem5,austinharris/gem5-riscv,joerocklin/gem5,yb-kim/gemV,yb-kim/gemV,austinharris/gem5-riscv,briancoutinho0905/2dsampling,zlfben/gem5,aclifton/cpeg853-gem5,rjschof/gem5,sobercoder/gem5,KuroeKurose/gem5,gedare/gem5,qizenguf/MLC-STT,gem5/gem5,Weil0ng/gem5,cancro7/gem5,gedare/gem5,HwisooSo/gemV-update,kaiyuanl/gem5,markoshorro/gem5,HwisooSo/gemV-update,powerjg/gem5-ci-test,TUD-OS/gem5-dtu,rjschof/gem5,briancoutinho0905/2dsampling,joerocklin/gem5,qizenguf/MLC-STT,gem5/gem5,SanchayanMaity/gem5,cancro7/gem5,HwisooSo/gemV-update,KuroeKurose/gem5,SanchayanMaity/gem5,gedare/gem5,austinharris/gem5-riscv,aclifton/cpeg853-gem5,powerjg/gem5-ci-test,rallylee/gem5,briancoutinho0905/2dsampling,aclifton/cpeg853-gem5,samueldotj/TeeRISC-Simulator,Weil0ng/gem5,gedare/gem5,SanchayanMaity/gem5,Weil0ng/gem5,qizenguf/MLC-STT,sobercoder/gem5,austinharris/gem5-riscv,cancro7/gem5,kaiyuanl/gem5,yb-kim/gemV,KuroeKurose/gem5,yb-kim/gemV,qizenguf/MLC-STT,TUD-OS/gem5-dtu,sobercoder/gem5,TUD-OS/gem5-dtu,rallylee/gem5,markoshorro/gem5,rjschof/gem5,SanchayanMaity/gem5,rallylee/gem5,sobercoder/gem5,HwisooSo/gemV-update,markoshorro/gem5,gem5/gem5,Weil0ng/gem5,rjschof/gem5,qizenguf/MLC-STT,sobercoder/gem5,gedare/gem5,sobercoder/gem5,austinharris/gem5-riscv,gem5/gem5,sobercoder/gem5,samueldotj/TeeRISC-Simulator,aclifton/cpeg853-gem5,rallylee/gem5,powerjg/gem5-ci-test,gem5/gem5,joerocklin/gem5,joerocklin/gem5,samueldotj/TeeRISC-Simulator,SanchayanMaity/gem5,kaiyuanl/gem5,gem5/gem5,yb-kim/gemV,TUD-OS/gem5-dtu,austinharris/gem5-riscv,gedare/gem5,joerocklin/gem5,kaiyuanl/gem5,HwisooSo/gemV-update,HwisooSo/gemV-update,zlfben/gem5,aclifton/cpeg853-gem5,yb-kim/gemV,KuroeKurose/gem5,TUD-OS/gem5-dtu,yb-kim/gemV,joerocklin/gem5,rjschof/gem5,KuroeKurose/gem5,cancro7/gem5,briancoutinho0905/2dsampling,zlfben/gem5,KuroeKurose/gem5,powerjg/gem5-ci-test,aclifton/cpeg853-gem5,gedare/gem5,zlfben/gem5,samueldotj/TeeRISC-Simulator,kaiyuanl/gem5,zlfben/gem5