internal/rosa/squashfs: enter correct directory

This was missed during the make helper migration.

Signed-off-by: Ophestra <cat@gensokyo.uk>

internal/rosa/squashfs.go

@@ -16,7 +16,6 @@ func (t Toolchain) newSquashfsTools() (pkg.Artifact, string) {
 		// uses source tree as scratch space
 		Writable: true,
 		Chmod:    true,
-		EnterSource: true,
 
 		Env: []string{
 			"CONFIG=1",
@@ -26,8 +25,8 @@ func (t Toolchain) newSquashfsTools() (pkg.Artifact, string) {
 			"COMP_DEFAULT=zstd",
 			"USE_PREBUILT_MANPAGES=y",
 		},
+		ScriptEarly: "cd squashfs-tools",
 	}, &MakeHelper{
-
 		SkipConfigure: true,
 		InPlace:       true,