net: phy: marvell: remove set but not used variable 'pause'

Fixes gcc '-Wunused-but-set-variable' warning:

drivers/net/phy/marvell.c: In function 'm88e1510_config_init':
drivers/net/phy/marvell.c:850:7: warning:
 variable 'pause' set but not used [-Wunused-but-set-variable]

It not used any more after commit 3c1bcc86 ("net: ethernet: Convert phydev
advertize and supported from u32 to link mode")

Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>