lorax: add i915.preliminary_hw_support=1 to kernel parameters

Fixes QubesOS/qubes-issues#1668

lorax-templates-qubes/templates/config_files/x86/isolinux.cfg

@@ -59,12 +59,12 @@ menu separator # insert an empty line
 label linux
   menu label ^Install @PRODUCT@
   kernel mboot.c32
-  append xen.gz console=none --- vmlinuz @ROOT@ quiet rhgb --- initrd.img
+  append xen.gz console=none --- vmlinuz @ROOT@ i915.preliminary_hw_support=1 quiet rhgb --- initrd.img
 label check
   menu label Test this ^media & install @PRODUCT@
   menu default
   kernel mboot.c32
-  append xen.gz console=none --- vmlinuz @ROOT@ quiet rhgb rd.live.check --- initrd.img
+  append xen.gz console=none --- vmlinuz @ROOT@ i915.preliminary_hw_support=1 quiet rhgb rd.live.check --- initrd.img
 menu separator # insert an empty line
 # utilities submenu
 menu begin ^Troubleshooting

lorax-templates-qubes/templates/config_files/x86/xen-efi.cfg

@@ -3,17 +3,17 @@ default=qubes
 
 [qubes-check]
 options=console=none
-kernel=vmlinuz @ROOT@ quiet rhgb rd.live.check
+kernel=vmlinuz @ROOT@ i915.preliminary_hw_support=1 quiet rhgb rd.live.check
 ramdisk=initrd.img
 
 [qubes]
 options=console=none
-kernel=vmlinuz @ROOT@ quiet rhgb
+kernel=vmlinuz @ROOT@ i915.preliminary_hw_support=1 quiet rhgb
 ramdisk=initrd.img
 
 [qubes-verbose]
 options=console=vga
-kernel=vmlinuz @ROOT@
+kernel=vmlinuz @ROOT@ i915.preliminary_hw_support=1
 ramdisk=initrd.img
 
 [qubes-rescue]