kbuild: fix compression errors getting ignored

A missing compression utility or other errors were not picked up by make
and an empty kernel image was produced.  By removing the &&, errors will
no longer be ignored.
Signed-off-by: Harald Seiler <hws@denx.de>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>

scripts/Makefile.lib

@@ -345,19 +345,19 @@ printf "%08x\n" $$dec_size |						\
 )
 
 quiet_cmd_bzip2 = BZIP2   $@
-      cmd_bzip2 = { cat $(real-prereqs) | bzip2 -9 && $(size_append); } > $@
+      cmd_bzip2 = { cat $(real-prereqs) | bzip2 -9; $(size_append); } > $@
 
 # Lzma
 # ---------------------------------------------------------------------------
 
 quiet_cmd_lzma = LZMA    $@
-      cmd_lzma = { cat $(real-prereqs) | lzma -9 && $(size_append); } > $@
+      cmd_lzma = { cat $(real-prereqs) | lzma -9; $(size_append); } > $@
 
 quiet_cmd_lzo = LZO     $@
-      cmd_lzo = { cat $(real-prereqs) | lzop -9 && $(size_append); } > $@
+      cmd_lzo = { cat $(real-prereqs) | lzop -9; $(size_append); } > $@
 
 quiet_cmd_lz4 = LZ4     $@
-      cmd_lz4 = { cat $(real-prereqs) | lz4c -l -c1 stdin stdout && \
+      cmd_lz4 = { cat $(real-prereqs) | lz4c -l -c1 stdin stdout; \
                   $(size_append); } > $@
 
 # U-Boot mkimage
@@ -400,7 +400,7 @@ quiet_cmd_uimage = UIMAGE  $@
 # big dictionary would increase the memory usage too much in the multi-call
 # decompression mode. A BCJ filter isn't used either.
 quiet_cmd_xzkern = XZKERN  $@
-      cmd_xzkern = { cat $(real-prereqs) | sh $(srctree)/scripts/xz_wrap.sh && \
+      cmd_xzkern = { cat $(real-prereqs) | sh $(srctree)/scripts/xz_wrap.sh; \
                      $(size_append); } > $@
 
 quiet_cmd_xzmisc = XZMISC  $@