gnupg: fix prompt of Config.in.host

It should be "host gnupg" and not "host-gnupg" to be consistent with
all other Config.in.host options.

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>

package/gnupg/Config.in.host

@@ -1,5 +1,5 @@
 config BR2_PACKAGE_HOST_GNUPG
-	bool "host-gnupg"
+	bool "host gnupg"
 	help
 	  GnuPG is the GNU project's complete and free implementation
 	  of the OpenPGP standard as defined by RFC4880. GnuPG allows