ARM: dts: mmp3: Drop usb-nop-xceiv from HSIC phy

"usb-nop-xceiv" is good enough if we don't lose the configuration done
by the firmware, but we'd really prefer a real driver.

Unfortunately, the PHY core is odd in that when the node is compatible
with "usb-nop-xceiv", it ignores the other compatible strings. Let's
just remove it.

Signed-off-by: Lubomir Rintel <lkundrak@v3.sk>
Cc: <stable@vger.kernel.org>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>