net/ice/base: refactor interface for flash read

net/ice/base: refactor interface for flash read

The ice_read_flash_module interface for reading from the various NVM
modules was introduced.

It's purpose is two-fold. First, it enables reading data from the CSS
header, used to allow accessing the image security revisions. Second, it
allowed reading from either the 1st or the 2nd NVM bank. This interface
was necessary because the device has two copies of each module. Only one
bank is active at a time, but it could be different for each module. The
driver had to determine which bank was active and then use that to
calculate the offset into the flash to read.

Future plans include allowing access to read not just from the active
flash bank, but also the inactive bank. This will be useful for enabling
display of the version information for a pending flash update.

The current abstraction in ice_read_flash_module is to specify the exact
bank to read. This requires callers to know whether to read from the 1st
or 2nd flash bank. This is the wrong abstraction level, since in most
cases the decision point from a caller's perspective is whether to read
from the active bank or the inactive bank.

Add a new ice_bank_select enumeration, used to indicate whether a flow
wants to read from the active, or inactive flash bank. Refactor
ice_read_flash_module to take this new enumeration instead of a raw
flash bank.

Have ice_read_flash_module select which bank to read from based on the
cached data we load during NVM initialization. With this change, it will
be come easier to implement reading version data from the inactive flash
banks in a future change.

Signed-off-by: Jacob Keller <jacob.e.keller@intel.com>
Signed-off-by: Qi Zhang <qi.z.zhang@intel.com>
Acked-by: Qiming Yang <qiming.yang@intel.com>