i2c: busses: make K1 driver default for SpacemiT platforms

i2c: busses: make K1 driver default for SpacemiT platforms

Enable I2C_K1 by default when ARCH_SPACEMIT is configured to ensure SD
card functionality works out-of-the-box.

SpacemiT K1 boards use I2C-controlled PMICs (like the P1 chip) to
provide SD card power supplies. Without the I2C_K1 driver enabled,
regulators cannot be controlled and SD card detection/operation fails.

Suggested-by: Margherita Milani <margherita.milani@amarulasolutions.com>
Suggested-by: Yixun Lan <dlan@kernel.org>
Signed-off-by: Iker Pedrosa <ikerpedrosam@gmail.com>
Reviewed-by: Yixun Lan <dlan@kernel.org>
Signed-off-by: Andi Shyti <andi.shyti@kernel.org>
Link: https://lore.kernel.org/r/20260526-orangepi-sd-card-i2c-v1-1-b92268bfd467@gmail.com