cpu/amd: Rename MCA status register

Change the defined name of MCI_STATUS (i.e. MCi_STATUS) to reflect its
MC0_STATUS address.

Change-Id: I97d2631a186965bb8b18f544ed9648b3a71f5fb0
Signed-off-by: Marshall Dawson <marshalldawson3rd@gmail.com>
Reviewed-on: https://review.coreboot.org/27922
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Martin Roth <martinroth@google.com>
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>

src/soc/amd/stoneyridge/cpu.c

@@ -126,7 +126,7 @@ static void model_15_init(struct device *dev)
 	msr.lo = 0;
 	msr.hi = 0;
 	for (i = 0 ; i < 6 ; i++)
-		wrmsr(MCI_STATUS + (i * 4), msr);
+		wrmsr(MC0_STATUS + (i * 4), msr);
 
 	setup_lapic();
 }