ARM: shmobile: defconfig: Enable TOUCHSCREEN_STMPE

Enable support for the stmpe i2c touch controller, which is used on the
iWave RZ/G1E platform.

Signed-off-by: Biju Das <biju.das.jz@bp.renesas.com>
Link: https://lore.kernel.org/r/20200806121704.3192-1-biju.das.jz@bp.renesas.com


Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>