cmd: fru: Add support for FRU commands

cmd: fru: Add support for FRU commands

This patch adds support for fru commands "fru capture"
and "fru display". The fru capture parses the FRU table
present at an address and stores in a structure for later
use. The fru display prints the content of captured structured
in a readable format.

As of now, it supports only common header and board area of FRU.
Also, its supports only English language code and ASCII8 format.

Signed-off-by: Siva Durga Prasad Paladugu <siva.durga.paladugu@xilinx.com>
Signed-off-by: Michal Simek <michal.simek@xilinx.com>