[libata] sata_fsl: Fix broken driver, add port multiplier (PMP) support

The following commit (4c9bf4e7):
libata: replace tf_read with qc_fill_rtf for non-SFF drivers

Broke the sata_fsl.c driver in 2.6.26-rc.  I know the following patch fixes
the issue, it clearly also adds port multipler support.  The current
2.6.26-rc driver is broken.

On boot with debug enabled we get something like (w/o this patch):

spurious interrupt!!, CC = 0x1
interrupt status 0x1
xx_scr_read, reg_in = 1
spurious interrupt!!, CC = 0x1
interrupt status 0x1
xx_scr_read, reg_in = 1
spurious interrupt!!, CC = 0x1
interrupt status 0x1
xx_scr_read, reg_in = 1

.. continues for ever.

This change fixes this as a side effect of adding port multiplier support.
Signed-off-by: Ashish Kalra <ashish.kalra@freescale.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>