mfd: simple-mfd-i2c: Remove select I2C_K1 from MFD_SPACEMIT_P1

select will force a symbol to a specific value without considering
its dependencies. As a result, the i2c-k1 driver will fail to build
when OF or COMMON_CLK are disabled.

The reason for removing I2C_K1 instead of adding a depends on condition
is to keep the possibility for other SoCs to use this PMIC.

Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202510211523.sSEVqPUQ-lkp@intel.com/
Acked-by: Alex Elder <elder@riscstar.com>
Signed-off-by: Troy Mitchell <troy.mitchell@linux.spacemit.com>
Link: https://lore.kernel.org/all/20251022004830-GYB1522542@gentoo.org/ [1]
Link: https://patch.msgid.link/20251027-p1-kconfig-fix-v2-1-49688f30bae8@linux.spacemit.com
Signed-off-by: Lee Jones <lee@kernel.org>