async: rename and redefine async_func_ptr

A function type is typically defined as
typedef ret_type (*func)(args..)

but async_func_ptr is not.  Redefine it.

Also rename async_func_ptr to async_func_t for _func_t suffix is more generic.

Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Arjan van de Ven <arjan@linux.intel.com>
diff --git a/arch/sh/drivers/pci/pcie-sh7786.c b/arch/sh/drivers/pci/pcie-sh7786.c
index c2c85f6..a162a7f 100644
--- a/arch/sh/drivers/pci/pcie-sh7786.c
+++ b/arch/sh/drivers/pci/pcie-sh7786.c
@@ -35,7 +35,7 @@
 
 static struct sh7786_pcie_hwops {
 	int (*core_init)(void);
-	async_func_ptr *port_init_hw;
+	async_func_t port_init_hw;
 } *sh7786_pcie_hwops;
 
 static struct resource sh7786_pci0_resources[] = {