boards: remove unnecessary I2C / SPI bus Kconfig enablement

We now 'select I2C' and/or SPI bus in Kconfig in the sensor driver
Kconfig's so there is no need to have boards do the following:

config I2C
       default y if SENSOR

config SPI
       default y if SENSOR

Signed-off-by: Kumar Gala <galak@kernel.org>