tty: fix comment of ASYNCB_SPD_HI

This comment does not reflect the actual code.  It should be 57600,
not 56000.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

include/uapi/linux/tty_flags.h

@@ -15,7 +15,7 @@
 #define ASYNCB_FOURPORT		 1 /* Set OU1, OUT2 per AST Fourport settings */
 #define ASYNCB_SAK		 2 /* Secure Attention Key (Orange book) */
 #define ASYNCB_SPLIT_TERMIOS	 3 /* [x] Separate termios for dialin/callout */
-#define ASYNCB_SPD_HI		 4 /* Use 56000 instead of 38400 bps */
+#define ASYNCB_SPD_HI		 4 /* Use 57600 instead of 38400 bps */
 #define ASYNCB_SPD_VHI		 5 /* Use 115200 instead of 38400 bps */
 #define ASYNCB_SKIP_TEST	 6 /* Skip UART test during autoconfiguration */
 #define ASYNCB_AUTO_IRQ		 7 /* Do automatic IRQ during