riscv: cpu: jh7110: Select SPL_ZERO_MEM_BEFORE_USE

Add Kconfig item for Starfive JH7110 to select SPL_ZERO_MEM_BEFORE_USE.

Signed-off-by: Bo Gan <ganboing@gmail.com>
Signed-off-by: Shengyu Qu <wiagn233@outlook.com>
Reviewed-by: Leo Yu-Chi Liang <ycliang@andestech.com>