Remove unnecessary variable for NVM checksum

[cramerj_intel.com]

Summary

We don't need the checksum itself, just the yay/nay that it was correct.

[sbruno]

Hrm ... I did a review of the code path here. the csum variable is a holder for the user to examine the checksum from the various functions. It *is* used as far as I can tell if non-NULL.

Is this your understanding as well?

[cramerj_intel.com]

The csum variable holds the checksum, yes. But nothing in attach() uses it afterwards. We only care about the return value of the function. I think the csum variable was added originally because ixgbe_validate_eeprom_checksum(), at that time, required a non-NULL input parameter...maybe? But then over time it was enhanced to allow a NULL parameter for drivers that didn't care about the csum value itself, but just the pass/fail return value of the function. In other words, ixgbe_validate_eeprom_checksum() will only populate "csum" if it's non-NULL. Grep for "checksum_val" to see what I mean.

I don't have a problem leaving the variable in if there was something to use it. Right now, nothing uses it. Is viewing the checksum something users are interested in?

[sbruno]

Its never exposed to userland and its not used in the driver in any code path. I don't know that anyone is using it, and I think its safe to change.

[sbruno]

Jeb:

What is your expectation with this review? Was Eric or I going to do something with it? If its not going to be committed, please abandon/close.

[cramerj_intel.com]

I'm going to abandon/close it today after I ask Eric how to do that. :) This patch will show up again soon, but along with the rest of the changes I'm adding.

[cramerj_intel.com]

Abandoning for now. Will resubmit this patch along with many more changes in a different review.