The AM572x Technical Reference Manual, SPRUHZ6H,
Revised November 2016 [1], shows recommended settings for the
SATA DPLL in Table 26-8. DPLL CLKDCOLDO Recommended Settings.

Use those settings in the driver. The TRM does not show
a value for 20MHz SYS_CLK so we use something close to the
26MHz setting.

[1] - http://www.ti.com/lit/ug/spruhz6h/spruhz6h.pdfSigned-off-by: Roger Quadros <rogerq@ti.com>
[nsekhar@ti.com: add exact TRM version to commit text]
Signed-off-by: Sekhar Nori <nsekhar@ti.com>
Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>