ARM: dts: dra7: fix DSS PLL clock mux registers

The clock nodes for DSS VIDEO1/2 and HDMI have wrong register addresses.
This patch fixes the addresses so that they point to
CM_CLKSEL_VIDEO1_PLL_SYS, CM_CLKSEL_VIDEO2_PLL_SYS and
CM_CLKSEL_HDMI_PLL_SYS.

Reported-by: Somnath Mukherjee <somnath@ti.com>
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>
Acked-by: Tero Kristo <t-kristo@ti.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>