platform/mellanox: Introduce support for Mellanox register access driver

Introduce new Mellanox platform driver to allow access to Mellanox
programmable device register space trough sysfs interface.
The driver purpose is to provide sysfs interface for user space for the
registers essential for system control and monitoring.
The sets of registers for sysfs access are supposed to be defined per
system type bases and include the registers related to system resets
operation, system reset causes monitoring and some kinds of mux selection.

Signed-off-by: Vadim Pasternak <vadimp@mellanox.com>
[dvhart: Kconfig typo fixes spotted by Randy Dunlap]
Signed-off-by: Darren Hart (VMware) <dvhart@infradead.org>