lib: sbi: Improve system reset platform operations

To implement the SBI SRST extension, we need two platform operations
for system reset:
1) system_reset_check() - This operation will check whether given
   reset type and reason are supported by the platform
2) system_reset() - This operation will do the actual platform
   system reset and it will not return if reset type and reason
   are supported by the platform

This patch updates system reset related code everywhere as-per above.

Signed-off-by: Anup Patel <anup.patel@wdc.com>
Reviewed-by: Atish Patra <atish.patra@wdc.com>

platform/generic/include/platform_override.h

@@ -20,7 +20,10 @@ struct platform_override {
 	int (*final_init)(bool cold_boot, const struct fdt_match *match);
 	void (*early_exit)(const struct fdt_match *match);
 	void (*final_exit)(const struct fdt_match *match);
-	int (*system_reset)(u32 reset_type, const struct fdt_match *match);
+	int (*system_reset_check)(u32 reset_type, u32 reset_reason,
+				  const struct fdt_match *match);
+	void (*system_reset)(u32 reset_type, u32 reset_reason,
+			     const struct fdt_match *match);
 	int (*fdt_fixup)(void *fdt, const struct fdt_match *match);
 };