ARM: shmobile: Enable BQ32000 rtc in shmobile_defconfig

The iWave RZ/G1M Q7 SOM supports RTC (TI BQ32000).
To increase hardware support enable the driver in the
shmobile_defconfig multiplatform configuration.

Signed-off-by: Biju Das <biju.das@bp.renesas.com>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>