xilinx: cmd: Add support for FRU commands

xilinx: cmd: 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, it
supports only English language code and ASCII8/BINARY formats.

fru_data variable is placed to data section because fru parser can be
called very early before bss is initialized. And also information needs to
be shared that's why it is exported via header.

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