phy: freescale: i.MX8 PHYs should depend on ARCH_MXC && ARM64

The Freescale/NXP i.MX8 USB3, MIPI DSI, and PCIE PHYs are only present
on the NXP i.MX8 family of SoCs.  Hence wrap the config symbols for
these PHYs inside a check for ARCH_MXC && ARM64, to prevent asking the
user about these drivers when configuring a kernel without NXP i.MX SoC
family support.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Guido Günther <agx@sigxcpu.org>
Link: https://lore.kernel.org/r/393868affd830016d35f0d9aba32ccd7098c8073.1641987369.git.geert+renesas@glider.be


Signed-off-by: Vinod Koul <vkoul@kernel.org>