arm64: kaslr: print PHYS_OFFSET in dump_kernel_offset()

When debug with kaslr, it is sometimes necessary to have PHYS_OFFSET to
perform linear virtual address to physical address translation.
Sometimes we're debugging with only few information such as a kernel log
and a symbol file, print PHYS_OFFSET in dump_kernel_offset() for that case.

Tested by:
echo c > /proc/sysrq-trigger
[   11.996161] SMP: stopping secondary CPUs
[   11.996732] Kernel Offset: 0x2522200000 from 0xffffff8008000000
[   11.996881] PHYS_OFFSET: 0xffffffeb40000000

Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Miles Chen <miles.chen@mediatek.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>

arch/arm64/kernel/setup.c

@@ -388,6 +388,7 @@ static int dump_kernel_offset(struct notifier_block *self, unsigned long v,
 	if (IS_ENABLED(CONFIG_RANDOMIZE_BASE) && offset > 0) {
 		pr_emerg("Kernel Offset: 0x%lx from 0x%lx\n",
 			 offset, KIMAGE_VADDR);
+		pr_emerg("PHYS_OFFSET: 0x%llx\n", PHYS_OFFSET);
 	} else {
 		pr_emerg("Kernel Offset: disabled\n");
 	}