include/u-boot, lib/zlib: add sources for zlib decompression

Add zlib (v1.2.11) uncompr() function to U-Boot. SquashFS depends on
this function to decompress data from a raw disk image. The actual
support for zlib into SquashFS sources will be added in a follow-up
commit.

Signed-off-by: Joao Marcos Costa <joaomarcos.costa@bootlin.com>
diff --git a/lib/zlib/zlib.c b/lib/zlib/zlib.c
index 7e15702..90e05e7 100644
--- a/lib/zlib/zlib.c
+++ b/lib/zlib/zlib.c
@@ -30,3 +30,6 @@
 #include "inflate.c"
 #include "zutil.c"
 #include "adler32.c"
+#if IS_ENABLED(CONFIG_ZLIB_UNCOMPRESS)
+#include "uncompr.c"
+#endif