ARM: keystone2: spl: add K2E SoC support

Keystone2 K2E SoC has slightly different spl pll settings then
K2HK, so correct this.

Acked-by: Murali Karicheri <m-karicheri2@ti.com>
Signed-off-by: Ivan Khoronzhuk <ivan.khoronzhuk@ti.com>