mmc: omap: don't select TPS65010

The MMC host driver should not select the pmic driver, since that
may have other dependencies, notably i2c in this case. It's not
clear what the exact requirement of the driver is, but to preserve
the behavior, this patch changes the 'select' into 'depends on',
meaning you now have to turn on TPS65010 explicitly and then
MMC_OMAP.

Found during randconfig build testing.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Cc: linux-omap@vger.kernel.org
Cc: Jarkko Nikula <jarkko.nikula@bitmer.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>