package: move busybox show others dependency to per-package

Having the BR2_PACKAGE_BUSYBOX_SHOW_OTHERS dependencies in
package/Config.in is not very practical: it makes this file not very
readable, and puts the dependency away from the package itself, which
can sometimes be confusing. Therefore, this commit moves the dependency
in each package Config.in file.

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>
diff --git a/package/ifplugd/Config.in b/package/ifplugd/Config.in
index cbb5128..c4b5b5b 100644
--- a/package/ifplugd/Config.in
+++ b/package/ifplugd/Config.in
@@ -2,6 +2,7 @@
 	bool "ifplugd"
 	# libdaemon uses fork()
 	depends on BR2_USE_MMU
+	depends on BR2_PACKAGE_BUSYBOX_SHOW_OTHERS
 	select BR2_PACKAGE_LIBDAEMON
 	help
 	  Ifplugd is a daemon which will automatically configure your