Clean up libpayload lpgcc and lpas scripts.

lpgcc and lpas are called by payload Makefiles to properly
build and link with libpayload.

Made lpas use the proper crosscompile AS, as lpgcc does with CC.
Added V=1 support to help users debug the build.
Fix basename $CC and $AS expansion.

Change-Id: Ia4dc8ba53ba7565521a79f1520155f3307b09f85
Signed-off-by: Marc Jones <marc.jones@se-eng.com>
Reviewed-on: http://review.coreboot.org/1993
Tested-by: build bot (Jenkins)
Reviewed-by: Ronald G. Minnich <rminnich@gmail.com>

payloads/libpayload/bin/lpas

@@ -27,17 +27,34 @@
 ## SUCH DAMAGE.
 
 # AS wrapper for libpayload
+if [ -z "${V}" ] && [ "${V}" = 1 ]; then
+	DEBUGME=1
+else
+	DEBUGME=0
+fi
 
-DEFAULT_PREFIX=/opt
+if [ $DEBUGME -eq 1 ]; then
+	echo "AS = $AS"
+fi
+
+if [ -n "$AS" ]; then
+b=`basename "$AS"`
+if [ "$b" = "lpas" ]; then
+AS=""
+fi
+fi
+
+if [ "$AS" != "" ]; then
+DEFAULT_AS=$AS
+else
 DEFAULT_AS=as
+fi
 
 BASE=`dirname $0`
 
 # This will set the _LIBDIR and _INCDIR variables used below
 . $BASE/lp.functions
 
-DEBUGME=0
-
 # This variable will contain the command line that the user wants to
 # pass to gas
 
@@ -69,4 +86,8 @@ done
 
 _ASFLAGS="--32 -I$_INCDIR"
 
+if [ $DEBUGME -eq 1 ]; then
+echo "$DEFAULT_AS $_ASFLAGS $CMDLINE"
+fi
+
 $DEFAULT_AS $_ASFLAGS $CMDLINE