ARM: dts: dra7: Add syscon-pllreset syscon to SATA PHY

This register is required to be passed to the SATA PHY driver
to workaround errata i783 (SATA Lockup After SATA DPLL Unlock/Relock).

Signed-off-by: Roger Quadros <rogerq@ti.com>
Acked-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>