ANDROID: GKI: scripts: Makefile: update the lz4 command (#2)

When the command was switched over from 'lz4c' to 'lz4', it changed the
meaning of '-c' in a subtle way. In the older lz4c tool, this '-cX'
seems to be a different flag, meaning the compression level. In the
newer lz4 tool, it means to compress to stdout. However, since kbuild
already specifies stdout as a file name, '-c' is superfluous, and
generates a warning:

Warning : stdout won't be used ! Do you want multiple input files (-m) ?

Fix it by removing the extra stdout flag.

Bug: 159285792
Bug: 160031736
Test: build/build.sh
Signed-off-by: Alistair Delva <adelva@google.com>
Change-Id: I96247317ccb31f224c6a8e6e453cddde5e0c2550

scripts/Makefile.lib

@@ -360,7 +360,7 @@ quiet_cmd_lzo = LZO     $@
 
 quiet_cmd_lz4 = LZ4     $@
       cmd_lz4 = { cat $(real-prereqs) | \
-                  $(LZ4) -c -l -12 --favor-decSpeed stdin stdout; \
+                  $(LZ4) -l -12 --favor-decSpeed stdin stdout; \
                   $(size_append); } > $@
 
 # U-Boot mkimage