[POWERPC] Update pSeries defconfig for SATA

Since the ipr driver now supports SATA and depends on libata,
enable libata to get built.
Signed-off-by: Brian King <brking@us.ibm.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>

arch/powerpc/configs/pseries_defconfig

@@ -506,7 +506,7 @@ CONFIG_SCSI_SAS_ATTRS=m
 # CONFIG_MEGARAID_NEWGEN is not set
 # CONFIG_MEGARAID_LEGACY is not set
 # CONFIG_MEGARAID_SAS is not set
-# CONFIG_ATA is not set
+CONFIG_ATA=y
 # CONFIG_SCSI_HPTIOP is not set
 # CONFIG_SCSI_BUSLOGIC is not set
 # CONFIG_SCSI_DMX3191D is not set