kernel/linux: fix using custom location

Currently, extract and patch are skipped as thus:
- using a custom directory of pre-installed headers
- a correctly named directory already exists

Otherwise, extract and patch are done.

The current second condition is wrong, because it allows the following
sequence to happen:
- a non-custom kernel is used
- a previous build only partially extracted the non-custom sources
- that p[revious build broke during extraction (eg. incomplete tarball...)
- a subsequent build will find a properly named directory, and will
thus skip extract and patch, which is wrong

Fix that by following the conditions in this table:

Type | Extract | Patch
----------------------+---------+-------
Pre-installed headers | N | N
custom directory | N | N
custom tarball | Y | N
mainstream tarball | Y | Y

Signed-off-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
Cc: David Holsgrove <david.holsgrove@xilinx.com>

diff -durN gcc-4.4.0.orig/gcc/config.gcc gcc-4.4.0/gcc/config.gcc

--- gcc-4.4.0.orig/gcc/config.gcc	2009-04-17 13:58:41.000000000 +0200

+++ gcc-4.4.0/gcc/config.gcc	2009-05-27 21:38:31.000000000 +0200

@@ -2121,7 +2121,7 @@

 	if test x${sh_multilibs} = x ; then

 		case ${target} in

 		sh64-superh-linux* | \

-		sh[1234]*)	sh_multilibs=${sh_cpu_target} ;;

+		sh[1234]*)	sh_multilibs=`cd ${srcdir}/config/sh ; echo t-mlib-sh[1-4]* | sed 's:t-mlib-sh:,m:g;s: ::g'` ;;

 		sh64* | sh5*)	sh_multilibs=m5-32media,m5-32media-nofpu,m5-compact,m5-compact-nofpu,m5-64media,m5-64media-nofpu ;;

 		sh-superh-*)	sh_multilibs=m4,m4-single,m4-single-only,m4-nofpu ;;

 		sh*-*-linux*)	sh_multilibs=m1,m3e,m4 ;;