ixgbe: remove magic constant in ixgbe_reset_hw_82599()

ixgbe_reset_hw_82599() resets the value of hw->mac.num_rar_entries to
pre-defined value of 128. Let's get rid of that hardcoded literal, and use
IXGBE_82599_RAR_ENTRIES instead, the same way the normal initialization
path does.

Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>