include: sbi_platform: Combine reboot and shutdown into one callback

We can achieve shutdown, cold reboot, and warm reboot using just
one sbi_platform callback so we combine system_reboot() and
system_shutdown() callbacks into one system_reset() callback.

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

include/sbi_utils/sys/htif.h

@@ -14,6 +14,6 @@ void htif_putc(char ch);
 
 int htif_getc(void);
 
-int htif_system_down(u32 type);
+int htif_system_reset(u32 type);
 
 #endif