omap3: zoom2/3: Register only 1 8250 port

There's no more serial ports available, so, doesn't make sense
to create 4 device nodes.
Signed-off-by: Sergio Aguirre <saaguirre@ti.com>

arch/arm/configs/omap_zoom2_defconfig

@@ -661,7 +661,7 @@ CONFIG_DEVKMEM=y
 CONFIG_SERIAL_8250=y
 CONFIG_SERIAL_8250_CONSOLE=y
 CONFIG_SERIAL_8250_NR_UARTS=32
-CONFIG_SERIAL_8250_RUNTIME_UARTS=4
+CONFIG_SERIAL_8250_RUNTIME_UARTS=1
 CONFIG_SERIAL_8250_EXTENDED=y
 CONFIG_SERIAL_8250_MANY_PORTS=y
 CONFIG_SERIAL_8250_SHARE_IRQ=y

arch/arm/configs/omap_zoom3_defconfig

@@ -680,7 +680,7 @@ CONFIG_DEVKMEM=y
 CONFIG_SERIAL_8250=y
 CONFIG_SERIAL_8250_CONSOLE=y
 CONFIG_SERIAL_8250_NR_UARTS=32
-CONFIG_SERIAL_8250_RUNTIME_UARTS=4
+CONFIG_SERIAL_8250_RUNTIME_UARTS=1
 CONFIG_SERIAL_8250_EXTENDED=y
 CONFIG_SERIAL_8250_MANY_PORTS=y
 CONFIG_SERIAL_8250_SHARE_IRQ=y