HV: make: drop double quotes in config.mk

Makefile takes all double quotes in variable definitions literally. Thus with
the following definition:

    FOO := "a"

expanding FOO in a file path results the following (which is invalid):

    SRC += a/b/${FOO}.c  --> SRC += a/b/"a".c

To avoid such issues, this patch drops the double quotes at the beginning and
end of the definition of symbols with string type.

Signed-off-by: Junjie Mao <junjie.mao@intel.com>
Acked-by: Anthony Xu <anthony.xu@intel.com>
Acked-by: Geoffroy VanCutsem <geoffroy.vancutsem@intel.com>

hypervisor/scripts/kconfig/kconfig.mk

@@ -17,7 +17,7 @@ $(HV_OBJDIR)/$(HV_CONFIG): oldconfig
 # it'll trigger endless re-execution of make.
 $(HV_OBJDIR)/$(HV_CONFIG_MK): $(HV_OBJDIR)/$(HV_CONFIG)
 	@mkdir -p $(dir $@)
-	@cp $< $@
+	@sed 's/="\(.*\)"$$/=\1/g' $(HV_OBJDIR)/$(HV_CONFIG) > $@
 
 $(HV_OBJDIR)/$(HV_CONFIG_H): $(HV_OBJDIR)/$(HV_CONFIG)
 	@mkdir -p $(dir $@)