Apply "nvme: Fix parsing of ANA log page" to 5.4

[Uday Shankar <ushankar@purestorage.com>]

Hello,

Please apply the patch "nvme: Fix parsing of ANA log page" to 5.4.

The commit ID in Linus's tree is:
	64fab7290dc3561729bbc1e35895a517eb2e549e

The patch was originally submitted on the linux-nvme mailing list, but
for reasons unknown to me it never landed on 5.4 - this thread indicates
it should have been accepted for 5.4.
https://lore.kernel.org/linux-nvme/1572303408-37913-1-git-send-email-psajeepa@purestorage.com/T/#u

Without the patch, we perform the check
	WARN_ON_ONCE(offset > ctrl->ana_log_size - sizeof(*desc))
at the end of the enclosing loop. This check only makes sense if we are
about to read another nvme_ana_group_desc from the ana_log_buf, but
that's not the case at the end of the last iteration of the loop. In the
last iteration, the warning fires and the function nvme_parse_ana_log
fails. When nvme native multipath is enabled, this translates into
failure to establish a connection to the controller.

The patch fixes the issue by moving the above check to a correct
position within the loop body.

Thanks,
Uday Shankar