mb/asrock/b85m_pro4: Correct PS/2 keyboard IRQ

No wonder why the PS/2 keyboard was being detected as a mouse!

Change-Id: I7080c8210d96b079a5c08d98554ed154141086a6
Signed-off-by: Angel Pons <th3fanbus@gmail.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/42398
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>
Reviewed-by: Felix Held <felix-coreboot@felixheld.de>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

src/mainboard/asrock/b85m_pro4/devicetree.cb

@@ -70,7 +70,7 @@ chip northbridge/intel/haswell
 					device pnp 2e.5   on		# PS/2 KBC
 						io  0x60 = 0x0060
 						io  0x62 = 0x0064
-						irq 0x70 = 12		# + Keyboard
+						irq 0x70 = 1		# + Keyboard
 						irq 0x72 = 12		# + Mouse
 					end
 					device pnp 2e.6   off end	# CIR