asm-generic/hyperv: Add missing function prototypes per -W1 warnings

Add two function prototypes for -W1 warnings generated by the
kernel test robot.
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Michael Kelley <mikelley@microsoft.com>
Link: https://lore.kernel.org/r/1615402069-39462-1-git-send-email-mikelley@microsoft.comSigned-off-by: Wei Liu <wei.liu@kernel.org>

include/asm-generic/mshyperv.h

@@ -94,6 +94,8 @@ static inline void vmbus_signal_eom(struct hv_message *msg, u32 old_msg_type)
 
 void hv_setup_vmbus_handler(void (*handler)(void));
 void hv_remove_vmbus_handler(void);
+void hv_setup_stimer0_handler(void (*handler)(void));
+void hv_remove_stimer0_handler(void);
 
 void hv_setup_kexec_handler(void (*handler)(void));
 void hv_remove_kexec_handler(void);