AMD Persimmon: mainboard.c: Make comment generic to reduce difference

Replace »persimmon« by »board« in comment to keep `diff` output
between boards small.

Change-Id: Ieae2a63782c488ae35f22eb30f5b1049200d12c8
Signed-off-by: Paul Menzel <paulepanter@users.sourceforge.net>
Reviewed-on: http://review.coreboot.org/2611
Tested-by: build bot (Jenkins)
Reviewed-by: Martin Roth <martin.roth@se-eng.com>

src/mainboard/amd/persimmon/mainboard.c

@@ -77,7 +77,7 @@ static void mainboard_enable(device_t dev)
 	/*
 	 * Initialize ASF registers to an arbitrary address because someone
 	 * long ago set things up this way inside the SPD read code.  The
-	 * SPD read code has been made generic and moved out of the persimmon
+	 * SPD read code has been made generic and moved out of the board
 	 * directory, so the ASF init is being done here.
 	 */
 	pm_iowrite(0x29, 0x80);