binman: add a new entry type for packing DDR PHY firmware images

i.MX95 needs to combine DDR PHY firmware images and their byte counts
together, so add a new entry type nxp-header-ddrfw for this requirement.

Signed-off-by: Alice Guo <alice.guo@nxp.com>
diff --git a/tools/binman/test/346_nxp_ddrfw_imx95.dts b/tools/binman/test/346_nxp_ddrfw_imx95.dts
new file mode 100644
index 0000000..889f6f2
--- /dev/null
+++ b/tools/binman/test/346_nxp_ddrfw_imx95.dts
@@ -0,0 +1,24 @@
+// SPDX-License-Identifier: GPL-2.0+
+
+/dts-v1/;
+
+/ {
+	#address-cells = <1>;
+	#size-cells = <1>;
+
+	binman {
+		imx-lpddr {
+			type = "nxp-header-ddrfw";
+
+			imx-lpddr-imem {
+				filename = "lpddr5_imem.bin";
+				type = "blob-ext";
+			};
+
+			imx-lpddr-dmem {
+				filename = "lpddr5_dmem.bin";
+				type = "blob-ext";
+			};
+		};
+	};
+};