riscv: dts: sophgo: add zfh for sg2042

sg2042 support Zfh ISA extension [1].

Link: https://occ-oss-prod.oss-cn-hangzhou.aliyuncs.com/resource//1737721869472/%E7%8E%84%E9%93%81C910%E4%B8%8EC920R1S6%E7%94%A8%E6%88%B7%E6%89%8B%E5%86%8C%28xrvm%29_20250124.pdf [1]

Signed-off-by: Han Gao <[email protected]>
Reviewed-by: Inochi Amaoto <[email protected]>
Reviewed-by: Nutty Liu <[email protected]>
Reviewed-by: Chen Wang <[email protected]>
Link: https://lore.kernel.org/r/bcaf5684c614959f49a9770bf3cd41096cee5fe6.1751698574.git.rabenda.cn@gmail.com
Signed-off-by: Inochi Amaoto <[email protected]>
Signed-off-by: Chen Wang <[email protected]>
Signed-off-by: Chen Wang <[email protected]>

Author: RevySR