Official EDK2 repository has VARIABLE_SUPPORT defaulting to EMU in UefiPayloadPkg, switch it to SMMSTORE if coreboot is built with SMMSTOREv2. This removes custom default of EDK2_CUSTOM_BUILD_PARAMS for EDK2_REPO_MRCHROMEBOX which is unnecessary now. Change-Id: Ic59f89c0f708f9b144bd35cd18870d0e1c65677d Signed-off-by: Sergii Dmytruk <sergii.dmytruk@3mdeb.com> Reviewed-on: https://review.coreboot.org/c/coreboot/+/83737 Reviewed-by: Matt DeVillier <matt.devillier@gmail.com> Reviewed-by: Maximilian Brune <maximilian.brune@9elements.com> Tested-by: build bot (Jenkins) <no-reply@coreboot.org>