Migrate grc blocks from xml to yaml

Convert the blocks using cmdline_converter.py script from
https://gist.githubusercontent.com/haakov/4228ff6a14486641add538483093e86b/raw/c861a840e31182ace2e74f5425e356cb4f8b183a/cmdline_converter.py

Change-Id: Iee5c611a2e100bd2fdf487611a867dc937d8c292
diff --git a/grc/decryption/gsm_decryption.block.yml b/grc/decryption/gsm_decryption.block.yml
new file mode 100644
index 0000000..8260907
--- /dev/null
+++ b/grc/decryption/gsm_decryption.block.yml
@@ -0,0 +1,31 @@
+# auto-generated by grc.converter
+
+id: gsm_decryption
+label: Decryption
+
+parameters:
+-   id: k_c
+    label: Kc session key
+    dtype: int_vector
+    default: '[0,0,0,0,0,0,0,0]'
+-   id: a5_version
+    label: A5 version
+    dtype: int
+    default: '1'
+
+inputs:
+-   domain: message
+    id: bursts
+
+outputs:
+-   domain: message
+    id: bursts
+asserts:
+- ${ a5_version > 0 }
+- ${ a5_version < 5 }
+
+templates:
+    imports: import grgsm
+    make: grgsm.decryption(${k_c}, ${a5_version})
+
+file_format: 1