board: ks2_evm: get rid of bogus CONFIG_LINUX_BOOT_PARAM_ADDR

CONFIG_LINUX_BOOT_PARAM_ADDR is not a valid configuration option. Do
just like what the rest of the world does.

Acked-by: Vitaly Andrianov <vitalya@ti.com>
Acked-By: Murali Karicheri <m-karicheri2@ti.com>
Reviewed-by: Tom Rini <trini@konsulko.com>
Signed-off-by: Nishanth Menon <nm@ti.com>