blackfin: BF538/9 serial uart support

Enable third UART on BF538/9
Signed-off-by: NMichael Hennerich <michael.hennerich@analog.com>
Signed-off-by: NBryan Wu <cooloney@kernel.org>
Signed-off-by: NAlan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

drivers/serial/Kconfig

@@ -770,7 +770,7 @@ config UART1_RTS_PIN
 
 config SERIAL_BFIN_UART2
 	bool "Enable UART2"
-	depends on SERIAL_BFIN && (BF54x)
+	depends on SERIAL_BFIN && (BF54x || BF538 || BF539)
 	help
 	  Enable UART2