usb: phy: remove phy-isp1301-omap driver

With the H2 and H3 board support removed from the driver, there
are actually no other users, so the entire driver can go away.

Link: https://lore.kernel.org/linux-arm-kernel/20221019173437.GB41568@darkstar.musicnaut.iki.fi/


Suggested-by: Aaro Koskinen <aaro.koskinen@iki.fi>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>