net: dsa: mt7530: fix incorrect test in mt753x_phylink_validate()

[ Upstream commit e5417cbf ]

Discussing one of the tests in mt753x_phylink_validate() with Landen
Chao confirms that the "||" should be "&&". Fix this.

Fixes: c288575f

 ("net: dsa: mt7530: Add the support of MT7531 switch")
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Link: https://lore.kernel.org/r/E1nRCF0-00CiXD-7q@rmk-PC.armlinux.org.uk
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>