binman: Add support for RISC-V OpenSBI fw_dynamic blob

Add an entry for RISC-V OpenSBI's 'fw_dynamic' firmware payload.

Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Rick Chen <rick@andestech.com>
Reviewed-by: Rick Chen <rick@andestech.com>
diff --git a/tools/binman/entries.rst b/tools/binman/entries.rst
index f1c3b7d..dcac700 100644
--- a/tools/binman/entries.rst
+++ b/tools/binman/entries.rst
@@ -761,6 +761,19 @@
 
 
 
+Entry: opensbi: RISC-V OpenSBI fw_dynamic blob
+----------------------------------------------
+
+Properties / Entry arguments:
+    - opensbi-path: Filename of file to read into entry. This is typically
+        called fw_dynamic.bin
+
+This entry holds the run-time firmware, typically started by U-Boot SPL.
+See the U-Boot README for your architecture or board for how to use it. See
+https://github.com/riscv/opensbi for more information about OpenSBI.
+
+
+
 Entry: powerpc-mpc85xx-bootpg-resetvec: PowerPC mpc85xx bootpg + resetvec code for U-Boot
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