drm/i915/dsi: Ensure that the ACPI adapter lookup overrides the bus num

drm/i915/dsi: Ensure that the ACPI adapter lookup overrides the bus num

Remove the i2c_bus_num >= 0 check from the adapter lookup function
as this would prevent ACPI bus number override. This check was mainly
there to return early if the bus number has already been found but we
anyway return in the next line if the slave address does not match.

Fixes: 4d7cc5d060f3 ("drm/i915/dsi: Parse the I2C element from the VBT MIPI sequence block (v3)")
Cc: Hans de Goede <hdegoede@redhat.com>
Cc: Nabendu Maiti <nabendu.bikash.maiti@intel.com>
Cc: Matt Roper <matthew.d.roper@intel.com>
Cc: Bob Paauwe <bob.j.paauwe@intel.com>
Cc: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Vivek Kasireddy <vivek.kasireddy@intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200118005848.20382-1-vivek.kasireddy@intel.com
(cherry picked from commit de409661c4c90d63cfc64579edbad0a6b10bd50d)
Signed-off-by: Jani Nikula <jani.nikula@intel.com>