usb: host: r8a66597-hcd: Remove set, then over-written, but never used variable 'tmp'

Looks like it's been this way since the driver's inception in 2007.

Fixes the following W=1 kernel build warning(s):

drivers/usb/host/r8a66597-hcd.c: In function ‘clear_all_buffer’:
drivers/usb/host/r8a66597-hcd.c:478:6: warning: variable ‘tmp’ set but not used [-Wunused-but-set-variable]
478 | u16 tmp;
| ^~~

Cc: Yoshihiro Shimoda <[e-mail]>
Signed-off-by: Lee Jones <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

drivers/usb/host/r8a66597-hcd.c

···
 static void clear_all_buffer(struct r8a66597 *r8a66597,
 			     struct r8a66597_pipe *pipe)
 {
-	u16 tmp;
-
 	if (!pipe || pipe->info.pipenum == 0)
 		return;
 
 	pipe_stop(r8a66597, pipe);
 	r8a66597_bset(r8a66597, ACLRM, pipe->pipectr);
-	tmp = r8a66597_read(r8a66597, pipe->pipectr);
-	tmp = r8a66597_read(r8a66597, pipe->pipectr);
-	tmp = r8a66597_read(r8a66597, pipe->pipectr);
+	r8a66597_read(r8a66597, pipe->pipectr);
+	r8a66597_read(r8a66597, pipe->pipectr);
+	r8a66597_read(r8a66597, pipe->pipectr);
 	r8a66597_bclr(r8a66597, ACLRM, pipe->pipectr);
 }