binman: Add support for adding a name prefix to entries

Sometimes we have several sections which repeat the same entries (e.g. for
a read-only and read-write version of the same section). It is useful to
be able to tell these entries apart by name.

Add a new 'name-prefix' property for sections, which causes all entries
within that section to have a given name prefix.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/tools/binman/README b/tools/binman/README
index 64e529f..42ed444 100644
--- a/tools/binman/README
+++ b/tools/binman/README
@@ -417,11 +417,13 @@
 	binman {
 		section@0 {
 			read-only;
+			name-prefix = "ro-";
 			size = <0x100000>;
 			u-boot {
 			};
 		};
 		section@1 {
+			name-prefix = "rw-";
 			size = <0x100000>;
 			u-boot {
 			};
@@ -437,6 +439,12 @@
 	Indicates that this section is read-only. This has no impact on binman's
 	operation, but his property can be read at run time.
 
+name-prefix:
+	This string is prepended to all the names of the binaries in the
+	section. In the example above, the 'u-boot' binaries which actually be
+	renamed to 'ro-u-boot' and 'rw-u-boot'. This can be useful to
+	distinguish binaries with otherwise identical names.
+
 
 Special properties
 ------------------