lib/Kconfig.debug: fix frv build failure

The build of frv allmodconfig was failing with the errors like:

  /tmp/cc0JSPc3.s: Assembler messages:
  /tmp/cc0JSPc3.s:1839: Error: symbol `.LSLT0' is already defined
  /tmp/cc0JSPc3.s:1842: Error: symbol `.LASLTP0' is already defined
  /tmp/cc0JSPc3.s:1969: Error: symbol `.LELTP0' is already defined
  /tmp/cc0JSPc3.s:1970: Error: symbol `.LELT0' is already defined

Commit 866ced9 ("kbuild: Support split debug info v4") introduced
splitting the debug info and keeping that in a separate file.  Somehow,
the frv-linux gcc did not like that and I am guessing that instead of
splitting it started copying.  The first report about this is at:

  https://lists.01.org/pipermail/kbuild-all/2015-July/010527.html.

I will try and see if this can work with frv and if still fails I will
open a bug report with gcc.  But meanwhile this is the easiest option to
solve build failure of frv.

Fixes: 866ced9 ("kbuild: Support split debug info v4")
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Sudip Mukherjee <[email protected]>
Reported-by: Fengguang Wu <[email protected]>
Cc: Andi Kleen <[email protected]>
Cc: David Howells <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

lib/Kconfig.debug

@@ -164,7 +164,7 @@ config DEBUG_INFO_REDUCED
 
 config DEBUG_INFO_SPLIT
 	bool "Produce split debuginfo in .dwo files"
-	depends on DEBUG_INFO
+	depends on DEBUG_INFO && !FRV
 	help
 	  Generate debug info into separate .dwo files. This significantly
 	  reduces the build directory size for builds with DEBUG_INFO,