Config.in.legacy: fix indentation (tab instead of spaces)

Found by check-package.

Fixes: 53a8c5150e5eeeb6dbbead0275dbf9141f507511
Fixes: https://gitlab.com/buildroot.org/buildroot/-/jobs/6406596540

Signed-off-by: Arnout Vandecappelle <arnout@mind.be>

Config.in.legacy

@@ -147,14 +147,14 @@ endif
 comment "Legacy options removed in 2024.05"
 
 config BR2_TOOLCHAIN_EXTERNAL_CODESOURCERY_AARCH64
-        bool "CodeSourcery AArch64 2014.11"
+	bool "CodeSourcery AArch64 2014.11"
 	select BR2_LEGACY
 	help
 	  The Sourcery CodeBench AArch64 toolchain has been removed,
 	  use an ARM/Bootlin/Linaro toolchain instead.
 
 config BR2_TOOLCHAIN_EXTERNAL_CODESOURCERY_ARM
-        bool "Sourcery CodeBench ARM 2014.05 has been removed"
+	bool "Sourcery CodeBench ARM 2014.05 has been removed"
 	select BR2_LEGACY
 	help
 	  The Sourcery CodeBench ARM toolchain has been removed, use