phy: ti: fix Kconfig warning and operator precedence

Fix Kconfig depends operator precedence to prevent a Kconfig warning:

WARNING: unmet direct dependencies detected for MUX_MMIO
  Depends on [n]: MULTIPLEXER [=m] && OF [=n]
  Selected by [m]:
  - PHY_AM654_SERDES [=m] && (OF [=n] && ARCH_K3 || COMPILE_TEST [=y]) && COMMON_CLK [=y]

Fixes: 71e2f5c5 ("phy: ti: Add a new SERDES driver for TI's AM654x SoC")
Fixes: 091876cc

 ("phy: ti: j721e-wiz: Add support for WIZ module present in TI J721E SoC")
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Cc: Vinod Koul <vkoul@kernel.org>
Cc: Kishon Vijay Abraham I <kishon@kernel.org>
Cc: linux-phy@lists.infradead.org
Cc: Arnd Bergmann <arnd@arndb.de>
Link: https://lore.kernel.org/r/20230110062529.22668-1-rdunlap@infradead.org
Signed-off-by: Vinod Koul <vkoul@kernel.org>