spi: intel: Keep the BIOS partition inside the first chip

If there are two flash chips connected flash regions can refer to the
second chip too. In this case we may see the following warning:

  mtd: partition "BIOS" extends beyond the end of device "0000:00:1f.5" --
  	size truncated to 0x400000

For this reason, check the BIOS partition size against the chip size and
make sure it stays within the that.

Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Link: https://lore.kernel.org/r/20240201121638.207632-2-mika.westerberg@linux.intel.com


Signed-off-by: Mark Brown <broonie@kernel.org>