ARM: 7845/1: sharpsl_param.c: fix invalid memory access for pxa devices

This fixes a regression for kernels after v3.2

After commit 72662e01
ARM: head.S: only include __turn_mmu_on in the initial identity mapping

Zaurus PXA devices call sharpsl_save_param() during fixup and hang on
boot because memcpy refers to physical addresses no longer valid if the
MMU is setup.
Zaurus collie (SA1100) is unaffected (function is called in init_machine).

The code was making assumptions and for PXA the virtual address
should have been used before.

Signed-off-by: Marko Katic <dromede@gmail.com>
Signed-off-by: Andrea Adami <andrea.adami@gmail.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>