Fix references to the no-longer-existent misc/ directory in comments, README files, and documentation

configs/sam4s-xplained-pro/Kconfig

@@ -1,6 +1,6 @@
 #
 # For a description of the syntax of this configuration file,
-# see misc/tools/kconfig-language.txt.
+# see the file kconfig-language.txt in the NuttX tools repository.
 #
 
 if ARCH_BOARD_SAM4S_XPLAINED_PRO

configs/sam4s-xplained-pro/README.txt

@@ -517,7 +517,7 @@ Configurations
     change any of these configurations using that tool, you should:
 
     a. Build and install the kconfig-mconf tool.  See nuttx/README.txt
-       and misc/tools/
+       see additional README.txt files in the NuttX tools repository.
 
     b. Execute 'make menuconfig' in nuttx/ in order to start the
        reconfiguration process.

configs/sam4s-xplained-pro/nsh/setenv.sh

@@ -65,7 +65,7 @@ fi
 
 # This is the Cygwin path to the location where I build the buildroot
 # toolchain.
-export TOOLCHAIN_BIN="${WD}/../misc/buildroot/build_arm_nofpu/staging_dir/bin"
+export TOOLCHAIN_BIN="${WD}/../buildroot/build_arm_nofpu/staging_dir/bin"
 
 # Add the path to the toolchain to the PATH varialble
 export PATH="${TOOLCHAIN_BIN}:/sbin:/usr/sbin:${PATH_ORIG}"