binman: btool: gzip: fix packer name so that binary can be found

The binary is looked on the system by the suffix of the packer class.
This means binman was looking for btool_gzip on the system and not gzip.

Therefore, let's pass "gzip" as the name so that it can be found and
used.

Fixes: 0f369d7 ("binman: Add gzip bintool")
Signed-off-by: Quentin Schulz <[email protected]>
Reviewed-by: Simon Glass <[email protected]>

tools/binman/btool/btool_gzip.py

@@ -27,5 +27,5 @@ class Bintoolbtool_gzip(bintool.BintoolPacker):
         man gzip
     """
     def __init__(self, name):
-        super().__init__(name, compress_args=[],
+        super().__init__("gzip", compress_args=[],
                          version_regex=r'gzip ([0-9.]+)')