ARM: DRA7xx: clocks: Update PLL values

ARM: DRA7xx: clocks: Update PLL values

Update PLL values.
SYS_CLKSEL value for 20MHz is changed to 2. In other platforms
SYS_CLKSEL value 2 represents reserved. But in sys_clk array
ind 1 is used for 13Mhz. Since other platforms are not using
13Mhz, reusing index 1 for 20MHz.

Signed-off-by: Lokesh Vutla <lokeshvutla@ti.com>
Signed-off-by: Sricharan R <r.sricharan@ti.com>