ARM: shmobile: defconfig: Drop useless SERIAL_8250_EXTENDED=y

SERIAL_8250_EXTENDED only serves as a guard for other Kconfig options,
none of which is enabled in shmobile_defconfig.
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>

arch/arm/configs/shmobile_defconfig

@@ -93,7 +93,6 @@ CONFIG_INPUT_ADXL34X=y
 # CONFIG_LEGACY_PTYS is not set
 CONFIG_SERIAL_8250=y
 CONFIG_SERIAL_8250_CONSOLE=y
-CONFIG_SERIAL_8250_EXTENDED=y
 CONFIG_SERIAL_8250_EM=y
 CONFIG_SERIAL_SH_SCI=y
 CONFIG_SERIAL_SH_SCI_NR_UARTS=20