rockchip: Move imply TPL_ROCKCHIP_COMMON_BOARD under SoC Kconfig symbol

rockchip: Move imply TPL_ROCKCHIP_COMMON_BOARD under SoC Kconfig symbol

The Kconfig symbol ROCKCHIP_COMMON_STACK_ADDR currently imply the
TPL_ROCKCHIP_COMMON_BOARD option when TPL=y. This is inconvenient for a
SoC with very limited SRAM to use a custom tpl.c together with the
common stack addresses.

Move any imply TPL_ROCKCHIP_COMMON_BOARD to under the SoC symbol, where
it belongs. Add the missing imply to RK3328 and PX30 use a SoC specific
tpl.c and only expect imply TPL_LIBGENERIC_SUPPORT.

Signed-off-by: Jonas Karlman <jonas@kwiboo.se>
Reviewed-by: Kever Yang <kever.yang@rock-chips.com>