prereq: SetupHostCommand: fix wrong check result

Tony has reported, that CI tools job is failing for him in macOS
container due to prereq check failure for GNU `install` utility.

Michael diagnosed it and from his traces it was clear, that the issue is
caused by a wrong return value in the success check case, so lets fix it
accordingly.

Fixes: f75204036c ("prereq-build: allow host command symlinks to update")
Reported-by: Tony Ambardar <itugrok@yahoo.com>
Diagnosed-by: Michael Pratt <mcpratt@pm.me>
Signed-off-by: Petr Štetiar <ynezz@true.cz>

include/prereq.mk

@@ -113,7 +113,7 @@ define SetupHostCommand
 						;; \
 				esac; \
 				ln -sf "$$$$$$$$bin" "$(STAGING_DIR_HOST)/bin/$(strip $(1))"; \
-				exit 1; \
+				exit 0; \
 			fi; \
 		fi; \
 	done; \