Config.in.legacy: remove redundant empty line

As reported by check-package.

Fixes: https://gitlab.com/buildroot.org/buildroot/-/jobs/1003084344

Signed-off-by: Arnout Vandecappelle (Essensium/Mind) <arnout@mind.be>

Config.in.legacy

@@ -156,7 +156,6 @@ config BR2_PACKAGE_LIBUPNP18
 	  CVE-2020-12695. The libupnp package (which has been updated to
 	  version 1.14.x) has been selected instead.
 
-
 config BR2_PACKAGE_PYTHON_PYCRYPTO
 	bool "python-pycrypto package removed"
 	select BR2_LEGACY