powerpc/mpc8xxx: check SPD length before using part number

Only use DDR DIMM part number if SPD has valid length, to prevent from
display garbage in case SPD doesn't cover these fields.
Signed-off-by: NYork Sun <yorksun@freescale.com>
Signed-off-by: NKumar Gala <galak@kernel.crashing.org>

arch/powerpc/cpu/mpc8xxx/ddr/ddr3_dimm_params.c

@@ -114,7 +114,8 @@ ddr_compute_dimm_parameters(const ddr3_spd_eeprom_t *spd,
 	 * and copying the part name in ASCII from the SPD onto it
 	 */
 	memset(pdimm->mpart, 0, sizeof(pdimm->mpart));
-	memcpy(pdimm->mpart, spd->mpart, sizeof(pdimm->mpart) - 1);
+	if ((spd->info_size_crc & 0xF) > 1)
+		memcpy(pdimm->mpart, spd->mpart, sizeof(pdimm->mpart) - 1);
 
 	/* DIMM organization parameters */
 	pdimm->n_ranks = ((spd->organization >> 3) & 0x7) + 1;