rockchip: rk3368: pmugrf: add definitions for os_reg[0..3]

rockchip: rk3368: pmugrf: add definitions for os_reg[0..3]

On the RK3368 we use a TPL-stage similar to Rockchip's DDR init
(i.e. it initialises DRAM, leaves some info for the next stage and
returns to the BootROM).  To allow compatibility with Rockchip's DDR
init code, we use the same register os_reg2 in pmugrf for passing
this info (i.e. DRAM size and configuration) between stages.

This change adds the definitions for os_reg[0] through os_reg[3] to
the pmugrf structure for the RK3368.

Signed-off-by: Philipp Tomsich <philipp.tomsich@theobroma-systems.com>
Reviewed-by: Simon Glass <sjg@chromium.org>