drm/xe/i2c: Don't rely on d3cold.allowed flag in system PM path

drm/xe/i2c: Don't rely on d3cold.allowed flag in system PM path

In S3 and above sleep states, the device can loose power regardless of
d3cold.allowed flag. Bring up I2C controller explicitly in system PM
path to ensure its normal operation after losing power.

v2: Cover S3 and above states (Rodrigo)

Fixes: 0ea07b69517a ("drm/xe/pm: Wire up suspend/resume for I2C controller")
Signed-off-by: Raag Jadav <raag.jadav@intel.com>
Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Link: https://lore.kernel.org/r/20250918103200.2952576-1-raag.jadav@intel.com
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>