Some RX errors, notably when disconnecting the cable, increase the RCSR
register. Once half full (0x7fff), an interrupt flood is generated. I
measured ~3k/s interrupts even after the RX errors transfer was
stopped.

Since we don't read and clear the RCSR register, we should disable this
interrupt.

Fixes: 87461f7a ("net: phy: DP83822 initial driver submission")
Signed-off-by: Enguerrand de Ribaucourt <enguerrand.de-ribaucourt@savoirfairelinux.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>