powerpc: Remove buggy 9-year-old test for binutils < 2.12.1

Recent binutils refuses to assemble AltiVec opcodes when in e500/SPE
mode, as some of those opcodes alias the "SPE" instructions.  This
triggers an ancient binutils version check even when building a kernel
with CONFIG_ALTIVEC disabled.

In theory, the check could be conditionalized on CONFIG_ALTIVEC, but in
practice it has long outlived its utility.  It is virtually impossible
to find binutils older than 2.12.1 (released 2002) in the wild anymore.
Even ancient RedHat Enterprise Linux 4 has binutils-2.14.

To fix the kernel build when done natively on e500 systems with this new
binutils, the test is simply removed.
Signed-off-by: Kyle Moffett <Kyle.D.Moffett@boeing.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

arch/powerpc/Makefile

@@ -255,12 +255,6 @@ checkbin:
 		echo 'disable kernel modules' ; \
 		false ; \
 	fi
-	@if ! /bin/echo dssall | $(AS) -many -o $(TOUT) >/dev/null 2>&1 ; then \
-		echo -n '*** ${VERSION}.${PATCHLEVEL} kernels no longer build ' ; \
-		echo 'correctly with old versions of binutils.' ; \
-		echo '*** Please upgrade your binutils to 2.12.1 or newer' ; \
-		false ; \
-	fi
 
 CLEAN_FILES += $(TOUT)