Fix libbeat BK crosscompile step (#37870)

libbeat/scripts/Makefile

@@ -87,7 +87,7 @@ SYSTEM_TESTS?=false ## @testing if true, "make test" and "make testsuite" run un
 STRESS_TESTS?=false ## @testing if true, "make test" and "make testsuite" run also run the stress tests
 STRESS_TEST_OPTIONS?=-timeout=20m -race -v
 GOX_OS?=linux darwin windows freebsd netbsd openbsd ## @Building List of all OS to be supported by "make crosscompile".
-GOX_OSARCH?=!darwin/arm !darwin/arm64 ## @building Space separated list of GOOS/GOARCH pairs to build by "make crosscompile".
+GOX_OSARCH?=!darwin/arm !darwin/386 !linux/386 !windows/386 !freebsd/386 !netbsd/386 !openbsd/386 !linux/ppc64 ## @building Space-separated list of GOOS/GOARCH pairs to exclude (unsupported by GO and generated by GOX) in the "make crosscompile" build.
 GOX_FLAGS?= ## @building Additional flags to append to the gox command used by "make crosscompile".
 # XXX: Should be switched back to `snapshot` once the Elasticsearch
 # snapshots are working. https://github.com/elastic/beats/pull/6416