serial: 8250: Move ns16550a_goto_hispeed() to local header

Prepare for 8250_core.c file split; move shared inline function
to local header file.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/tty/serial/8250/8250.h

@@ -21,7 +21,6 @@ struct uart_8250_dma {
 
 	/* Filter function */
 	dma_filter_fn		fn;
-
 	/* Parameter to the filter function */
 	void			*rx_param;
 	void			*tx_param;
@@ -198,3 +197,20 @@ static inline int serial8250_request_dma(struct uart_8250_port *p)
 }
 static inline void serial8250_release_dma(struct uart_8250_port *p) { }
 #endif
+
+static inline int ns16550a_goto_highspeed(struct uart_8250_port *up)
+{
+	unsigned char status;
+
+	status = serial_in(up, 0x04); /* EXCR2 */
+#define PRESL(x) ((x) & 0x30)
+	if (PRESL(status) == 0x10) {
+		/* already in high speed mode */
+		return 0;
+	} else {
+		status &= ~0xB0; /* Disable LOCK, mask out PRESL[01] */
+		status |= 0x10;  /* 1.625 divisor for baud_base --> 921600 */
+		serial_out(up, 0x04, status);
+	}
+	return 1;
+}

drivers/tty/serial/8250/8250_core.c

@@ -903,23 +903,6 @@ static int broken_efr(struct uart_8250_port *up)
 	return 0;
 }
 
-static inline int ns16550a_goto_highspeed(struct uart_8250_port *up)
-{
-	unsigned char status;
-
-	status = serial_in(up, 0x04); /* EXCR2 */
-#define PRESL(x) ((x) & 0x30)
-	if (PRESL(status) == 0x10) {
-		/* already in high speed mode */
-		return 0;
-	} else {
-		status &= ~0xB0; /* Disable LOCK, mask out PRESL[01] */
-		status |= 0x10;  /* 1.625 divisor for baud_base --> 921600 */
-		serial_out(up, 0x04, status);
-	}
-	return 1;
-}
-
 /*
  * We know that the chip has FIFOs.  Does it have an EFR?  The
  * EFR is located in the same register position as the IIR and