localmodconfig: Add config depends by default settings

Currently localmodconfig will miss dependencies from the default option.
For example:

config FOO
	default y if BAR || ZOO

If FOO is needed for a module and is set to '=m', and so are BAR or ZOO,
localmodconfig will not see that BOO or ZOO are also needed for the foo
module, and will incorrectly disable them.

Link: http://lkml.kernel.org/r/20131218175137.162937350@goodmis.org
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>