[PATCH v2] powerpc/boot: Fix dash warning

[Madhavan Srinivasan <maddy@linux.ibm.com>]

Commit b2accfe7ca5b '("powerpc/boot: Check for ld-option support")' suppressed
linker warnings, but the expressed used did not go well with POSIX shell (dash)
resulting with this warning

arch/powerpc/boot/wrapper: 237: [: 0: unexpected operator
ld: warning: arch/powerpc/boot/zImage.epapr has a LOAD segment with RWX permissions

Fix the check to handle the reported warning. Patch also fixes
couple of shellcheck reported errors for the same line.

In arch/powerpc/boot/wrapper line 237:
if [ $(${CROSS}ld -v --no-warn-rwx-segments &>/dev/null; echo $?) -eq 0 ]; then
     ^-- SC2046 (warning): Quote this to prevent word splitting.
       ^------^ SC2086 (info): Double quote to prevent globbing and word splitting.
                                            ^---------^ SC3020 (warning): In POSIX sh, &> is undefined.

Fixes: b2accfe7ca5b '("powerpc/boot: Check for ld-option support")'
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Suggested-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Madhavan Srinivasan <maddy@linux.ibm.com>
---
Changelog v1:
- modified the check to use the command exit
  state instead explicit checking with exit code
  
Patch applies on top of powerpc/fixes

 arch/powerpc/boot/wrapper | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/powerpc/boot/wrapper b/arch/powerpc/boot/wrapper
index 267ca6d4d9b3..3d8dc822282a 100755
--- a/arch/powerpc/boot/wrapper
+++ b/arch/powerpc/boot/wrapper
@@ -234,7 +234,7 @@ fi
 
 # suppress some warnings in recent ld versions
 nowarn="-z noexecstack"
-if [ $(${CROSS}ld -v --no-warn-rwx-segments &>/dev/null; echo $?) -eq 0 ]; then
+if "${CROSS}ld" -v --no-warn-rwx-segments >/dev/null 2>&1; then
 	nowarn="$nowarn --no-warn-rwx-segments"
 fi
 
-- 
2.49.0