fm10k: demote BUG_ON() to WARN_ON() where appropriate

We don't need to crash the kernel in this instance so just warn about the
condition and play on.

Signed-off-by: Bruce Allan <bruce.w.allan@intel.com>
Tested-by: Krishneil Singh <Krishneil.k.singh@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>