KERNEL: Add basic infrastructure for tracking of extended resources.

[mmel]

Summary

This patch allows us to track consumed extended resources (clocks,
resets, regulator) per device basis. Also, we can automatically release
all extended resources in device_detach().

[andrew]

How is this expected to be used? An example consumer of the api would be useful.

[mmel]

It will be used in upcoming clk/regulator/reset framework.
Example of usage can be found in https://github.com/strejda/tegra/blob/master/sys/dev/clk/clk.c