PCMCIA: Alchemy Don't select 64BIT_PHYS_ADDR in Kconfig.

For Alchemy 64BIT_PHYS_ADDR is already always set in arch/mips/Kconfig.
Also 64BIT_PHYS_ADDR is about to be removed.

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>