net: macb: fix for pause frame receive enable bit

PAE bit of NCFGR register, when set, pauses transmission
if a non-zero 802.3 classic pause frame is received.

Fixes: 7897b071 ("net: macb: convert to phylink")
Signed-off-by: Parshuram Thombare <pthombar@cadence.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>