Added support for reload_config

This service does not need to start so early (even
before the netwrok is up). Start it after
the device is mostly up and operational.

Compile-tested on: ipq806x
Runtime-tested on: ipq806x

Signed-off-by: Marc Benoit <marcb62185@gmail.com>

Added the ability to change sampling interval
and provide a list of IRQ's to ignore
via /etc/config/irqbalance

Signed-off-by: Marc Benoit <marcb62185@gmail.com>

Add support for uci config file.

Only a global 'enabled" switch has been implemented so far.

* Default config disables irqbalance initially, so that there is
  no change with the previous behaviour (and the possibly existing
  separate launch scripts in people's builds).

Config file and init script can be later extended for irqbalance
options like the oneshot mode or the evaluation interval

(Also change the init file to use tabs)

Signed-off-by: Hannu Nyman <hannu.nyman@iki.fi>

Signed-off-by: Aleksandr Mezin <mezin.alexander@gmail.com>