ARM: bcm_defconfig: Re-enable QCA7000 SPI driver

Since commit b2f98200 ("net: qualcomm: make qca_7k_common a
separate kernel module") the config parameter for the QCA7000 SPI
driver has changed. So re-enable the QCA7000 SPI driver in all
defconfigs, so we can use the qca7000-overlay again.

Signed-off-by: Stefan Wahren <stefan.wahren@i2se.com>