makefile: Do setup of the install target more flexible

- Add possibility to setup include, libs, firmware and docs paths.

- Change the default installation paths for include, libs, firmware
  and docs to meet FHS [1].

[1] https://refspecs.linuxfoundation.org/FHS_3.0/fhs/index.html



Signed-off-by: Nikita Ermakov <coffe92@gmail.com>
Reviewed-by: Anup Patel <anup.patel@wdc.com>