README.hardware: Replace atom-pc with genericx86

Update README.hardware to reflect the recent replacement of
atom-pc with genericx86.

(From meta-yocto rev: 632d92087cebb11ff9cb0110f9dae01d04bdd83b)

Signed-off-by: Darren Hart <dvhart@linux.intel.com>
Cc: Ross Burton <ross.burton@intel.com>
Cc: Scott Rifenbark <scott.m.rifenbark@intel.com>
Signed-off-by: Saul Wold <sgw@linux.intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

README.hardware

@@ -59,7 +59,7 @@ Consumer Devices
 
 The following consumer devices are supported by the meta-yocto-bsp layer:
 
-  * Intel Atom based PCs and devices (atom-pc)
+  * Intel x86 based PCs and devices (genericx86)
 
 For more information see the device's section below. The appropriate MACHINE
 variable value corresponding to the device is given in brackets.
@@ -70,10 +70,10 @@ variable value corresponding to the device is given in brackets.
                       ===============================
 
 
-Intel Atom based PCs and devices (atom-pc)
+Intel x86 based PCs and devices (genericx86)
 ==========================================
 
-The atom-pc MACHINE is tested on the following platforms:
+The genericx86 MACHINE is tested on the following platforms:
 
   o Asus EeePC 901
   o Acer Aspire One
@@ -93,7 +93,7 @@ device as the following commands are run as root and are not reversable.
 USB Device:
   1. Build a live image. This image type consists of a simple filesystem
      without a partition table, which is suitable for USB keys, and with the
-     default setup for the atom-pc machine, this image type is built
+     default setup for the genericx86 machine, this image type is built
      automatically for any image you build. For example:
 
      $ bitbake core-image-minimal
@@ -101,7 +101,7 @@ USB Device:
   2. Use the "dd" utility to write the image to the raw block device. For
      example:
 
-     # dd if=core-image-minimal-atom-pc.hddimg of=/dev/sdb
+     # dd if=core-image-minimal-genericx86.hddimg of=/dev/sdb
 
   If the device fails to boot with "Boot error" displayed, or apparently
   stops just after the SYSLINUX version banner, it is likely the BIOS cannot
@@ -142,7 +142,7 @@ USB Device:
 
      # mkdir /tmp/image
      # mkdir /tmp/usbkey
-     # mount -o loop core-image-minimal-atom-pc.hddimg  /tmp/image
+     # mount -o loop core-image-minimal-genericx86.hddimg  /tmp/image
      # mount /dev/sdb4 /tmp/usbkey
      # cp -rf /tmp/image/* /tmp/usbkey