BaseTools: Add GENFWHII_FLAGS to fix VS2026 GenFW build issue

Signed-off-by: Yang Gang <yanggang@byosoft.com.cn>

Author: YangGangUEFI

BaseTools/Conf/tools_def.template

@@ -823,6 +823,7 @@ NOOPT_VS2022_AARCH64_DLINK_FLAGS   = /NOLOGO /NODEFAULTLIB /IGNORE:4001 /IGNORE:
 *_VS2026_*_VFRPP_FLAGS     = /nologo /E /TC /DVFRCOMPILE /FI$(MODULE_NAME)StrDefs.h
 *_VS2026_*_DLINK2_FLAGS    = /WHOLEARCHIVE
 *_VS2026_*_ASM16_PATH      = DEF(VS2026_BIN_IA32)\ml.exe
+*_VS2026_*_GENFWHII_FLAGS  = --hiipackage
 *_VS2026_*_DEPS_FLAGS      = DEF(MSFT_DEPS_FLAGS)
 ##################
 # ASL definitions