mvebu: enable SATA port multiplier support

Some of the Marvell targets have functional SATA port multiplier
support, which is required for multi-bay eSATA enclosures.  Enable
kernel support by setting CONFIG_SATA_PMP.

Closes: FS#1232 and FS#547

Signed-off-by: Jeremiah McConnell <miah@miah.com>

target/linux/mvebu/config-4.14

@@ -422,6 +422,7 @@ CONFIG_RWSEM_SPIN_ON_OWNER=y
 CONFIG_RWSEM_XCHGADD_ALGORITHM=y
 CONFIG_SATA_AHCI_PLATFORM=y
 CONFIG_SATA_MV=y
+CONFIG_SATA_PMP=y
 # CONFIG_SCHED_INFO is not set
 CONFIG_SCSI=y
 CONFIG_SENSORS_PWM_FAN=y