ARM: dts: dra7xx-clocks: Add missing clocks for second PCIe PHY instance

Added missing clocks used by second instance of PCIe PHY.
The documention for this nodes can be found @ ../bindings/clock/ti/gate.txt.

Cc: Rajendra Nayak <rnayak@ti.com>
Cc: Tero Kristo <t-kristo@ti.com>
Cc: Paul Walmsley <paul@pwsan.com>
Cc: Tony Lindgren <tony@atomide.com>
Cc: Rob Herring <robh+dt@kernel.org>
Cc: Pawel Moll <pawel.moll@arm.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Kumar Gala <galak@codeaurora.org>
Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>