x86/mce/AMD: Get address from already initialized block

The block address is saved after the block is initialized when
threshold_init_device() is called.

Use the saved block address, if available, rather than trying to
rediscover it.

This will avoid a call trace, when resuming from suspend, due to the
rdmsr_safe_on_cpu() call in get_block_address(). The rdmsr_safe_on_cpu()
call issues an IPI but we're running with interrupts disabled. This
triggers:

    WARNING: CPU: 0 PID: 11523 at kernel/smp.c:291 smp_call_function_single+0xdc/0xe0

Signed-off-by: Yazen Ghannam <yazen.ghannam@amd.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: <stable@vger.kernel.org> # 4.14.x
Cc: Borislav Petkov <bp@alien8.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tony Luck <tony.luck@intel.com>
Cc: linux-edac <linux-edac@vger.kernel.org>
Link: http://lkml.kernel.org/r/20180221101900.10326-8-bp@alien8.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>