According to the SFI specification irq number 0xFF means device has no
interrupt or interrupt attached via GPIO.

Currently, we don't handle this special case and set irq field in
*_board_info structs to 255.  It leads to confusion in some drivers.
Accelerometer driver tries to register interrupt 255, fails and prints
"Cannot get IRQ" to dmesg.
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>