ice: discover and store size of available flash

ice: discover and store size of available flash

When reading from the NVM using a flat address, it is useful to know the
upper bound on the size of the flash contents. This value is not stored
within the NVM.

We can determine the size by performing a bisection between upper and
lower bounds. It is known that the size cannot exceed 16 MB (offset of
0xFFFFFF).

Use a while loop to bisect the upper and lower bounds by reading one
byte at a time. On a failed read, lower the maximum bound. On
a successful read, increase the lower bound.

Save this as the flash_size in the ice_nvm_info structure that contains
data related to the NVM.

The size will be used in a future patch for implementing full NVM read
via ethtool's GEEPROM command.

The maximum possible size for the flash is bounded by the size limit for
the NVM AdminQ commands. Add a new macro, ICE_AQC_NVM_MAX_OFFSET, which
can be used to represent this upper bound.

Signed-off-by: Jacob Keller <jacob.e.keller@intel.com>
Reviewed-by: Jesse Brandeburg <jesse.brandeburg@intel.com>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>