Merge pull request #11047 from dezgeg/pr-raspi-kheaders-defconfig

platforms.nix: Use bcm2835_defconfig for RPi kernelHeadersBaseConfig

pkgs/top-level/platforms.nix

···
   raspberrypi = {
     name = "raspberrypi";
     kernelMajor = "2.6";
-    kernelHeadersBaseConfig = "kirkwood_defconfig";
+    kernelHeadersBaseConfig = "bcm2835_defconfig";
     kernelBaseConfig = "bcmrpi_defconfig";
     kernelArch = "arm";
     kernelAutoModules = false;