qemu_x86: update to kernel 3.1 and add readme

Signed-off-by: Gustavo Zacarias <gustavo@zacarias.com.ar>
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>

board/qemu/x86/readme.txt

@@ -0,0 +1,5 @@
+Run the emulation with:
+
+  qemu-system-x86_64 -M pc -kernel output/images/bzImage -drive file=output/images/rootfs.ext2,if=ide -append root=/dev/sda
+
+The login prompt will appear in the graphical window.

configs/qemu_x86_defconfig

@@ -4,6 +4,7 @@ BR2_x86_pentiumpro=y
 
 # system
 BR2_TARGET_GENERIC_GETTY=y
+BR2_TARGET_GENERIC_GETTY_PORT="tty1"
 
 # filesystem
 BR2_TARGET_ROOTFS_EXT2=y
@@ -12,6 +13,6 @@ BR2_TARGET_ROOTFS_EXT2=y
 # Kernel
 BR2_LINUX_KERNEL=y
 BR2_LINUX_KERNEL_CUSTOM_VERSION=y
-BR2_LINUX_KERNEL_CUSTOM_VERSION_VALUE="3.0.4"
+BR2_LINUX_KERNEL_CUSTOM_VERSION_VALUE="3.1"
 BR2_LINUX_KERNEL_USE_CUSTOM_CONFIG=y
-BR2_LINUX_KERNEL_CUSTOM_CONFIG_FILE="board/qemu/x86/linux-3.0.config"
+BR2_LINUX_KERNEL_CUSTOM_CONFIG_FILE="board/qemu/x86/linux-3.1.config"