title: buildroot for arm kernel defconfig
body: <p>I am trying to build a buildroot with kernel image, and after doing <code>make menuconfig</code> and <code>make</code>, I am getting:</p>
  
  <pre><code>No kernel defconfig name specified, check your BR2_LINUX_KERNEL_DEFCONFIG setting
  </code></pre>
  
  <p>I can set a string to the <code>defconfig</code>, but I don't know what to put there.</p>
  
  <p>My target system is an AT91SAM9RL board.</p>
  
  <p><strong>edit</strong>: I found out there are some pre-made config files to some devices, actually not exactly matching to my target.</p>