config: Don't append extra $ to TOOLS_PATH_OVERRIDE

This fixes build system error:

  internal error: panic in GenerateBuildActions for module "generated_kernel_includes"
  error parsing Command param: invalid character after '$' at byte offset 579

Change-Id: I3f788ff61fc101b7682d5c64d0e9aa2aba48c49b

config/BoardConfigSoong.mk

@@ -1,4 +1,4 @@
-PATH_OVERRIDE_SOONG := $(shell echo $(TOOLS_PATH_OVERRIDE) | sed -e 's|$$|$$$$|g')
+PATH_OVERRIDE_SOONG := $(shell echo $(TOOLS_PATH_OVERRIDE))
 
 # Add variables that we wish to make available to soong here.
 EXPORT_TO_SOONG := \