localmodconfig: Check if configs are already set for selects

localmodconfig: Check if configs are already set for selects

There are some cases that a required module does not have a prompt
and needs to have another module enabled that selects it to be set.
As localmodconfig is conservative and tries to make the minimum config
without breaking the user's kernel, or keeping the user from using
devices that were loaded when the lsmod was done, all modules that
select this module will also be enabled.

If you needed module A, but module A did not have a prompt but needed
module B to be selected, localmodconfig would make sure B was still
enabled. If not only B selected A, but C, D, E, F, and G also
selected A, then all of those would also be included, as well as the
modules they depend on. This ballooned the number of configs that
localmodconfig would keep.

The fix here is to process the depends first, and then record those
configs that did not have a prompt and needed to be selected.
After the depends are done, check what configs are needed to select
the configs in the list, and if a config that selects it is already
set, then we don't need to do anything else.

If no config that selects the config is set, then just pick one and
try again.

This change brought down the number of selected modules from 290
to 67! Both before and after were run against a config that had 3095
modules enabled.

Tested-by: John David Yost <johnyost@ptd.net> # AlleyTrotter
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>