Do not run "mkdir ./" in codebase root directly

Test: grep "mkdir -p \.\/" out/build-*.ninja
Bug: 185197550
Change-Id: Ic9568ff91006b0cf362d5b5b105eb25ea3e228a8
diff --git a/core/definitions.mk b/core/definitions.mk
index b15ce84..2951c05 100644
--- a/core/definitions.mk
+++ b/core/definitions.mk
@@ -2765,7 +2765,7 @@
 define _symlink-file
 $(3): $(1)
 	@echo "Symlink: $$@ -> $(2)"
-	@mkdir -p $(dir $$@)
+	@mkdir -p $$(dir $$@)
 	@rm -rf $$@
 	$(hide) ln -sf $(2) $$@
 $(3): .KATI_SYMLINK_OUTPUTS := $(3)