amd/mct/ddr3: Correctly configure CsMux67

The existing logic to set up CsMux67 used an incorrect mask
and comparison value due to a copy + paste editing error.

Use the correct mask and comparison value for the last two
values.

Commit cf1cb5b2d4 did the same
for CsMux45 but missed this one.

Change-Id: Ib97ca89535b8291397d42eca69e217c21a9dd937
Signed-off-by: Patrick Georgi <pgeorgi@chromium.org>
Reviewed-on: https://review.coreboot.org/25994
Reviewed-by: Stefan Reinauer <stefan.reinauer@coreboot.org>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

src/northbridge/amd/amdmct/mct_ddr3/mctproc.c

@@ -58,7 +58,7 @@ u32 mct_SetDramConfigMisc2(struct DCTStatStruc *pDCTstat,
 			if (((((f2x80 >> 4) & 0xf) == 0x7) || (((f2x80 >> 4) & 0xf) == 0x9))
 				&& ((f2x64 & 0x3) == 0x3))
 				cs_mux_67 = 1;
-			else if (((((f2x80 >> 4) & 0xa) == 0x7) || (((f2x80 >> 4) & 0xb) == 0x9))
+			else if (((((f2x80 >> 4) & 0xf) == 0xa) || (((f2x80 >> 4) & 0xf) == 0xb))
 				&& ((f2x64 & 0x3) > 0x1))
 				cs_mux_67 = 1;
 			else