microblaze: Add a missing single quote to make 'make help' happy

'make ARCH=microblaze help' fails with the following error due to a
missing single quote.

/bin/sh: -c: line 0: unexpected EOF while looking for matching `''
/bin/sh: -c: line 1: syntax error: unexpected end of file
make: *** [help] Error 2
Signed-off-by: Arun Bhanu <arun@bhanu.net>
Signed-off-by: Michal Simek <monstr@monstr.eu>

arch/microblaze/Makefile

@@ -84,7 +84,7 @@ define archhelp
   echo '* linux.bin    - Create raw binary'
   echo '  linux.bin.gz - Create compressed raw binary'
   echo '  simpleImage.<dt> - ELF image with $(arch)/boot/dts/<dt>.dts linked in'
-  echo '                   - stripped elf with fdt blob
+  echo '                   - stripped elf with fdt blob'
   echo '  simpleImage.<dt>.unstrip - full ELF image with fdt blob'
   echo '  *_defconfig      - Select default config from arch/microblaze/configs'
   echo ''