inst_type/I: Add I-type instruction schema (riscv-software-src#883)

In (riscv-software-src#686), a new instruction schema was created
for types/subtypes. This commit add the schema
for the I-type. It is also part of effort in (riscv-software-src#655).

Signed-off-by: Usman Akinyemi <[email protected]>

Author: Unique-Usman

spec/std/isa/inst_type/I.yaml

@@ -0,0 +1,22 @@
+# Copyright (c) 2025 Usman Akinyemi
+# SPDX-License-Identifier: BSD-3-Clause-Clear
+
+# yaml-language-server: $schema=../../schemas/inst_type_schema.json#
+
+$schema: inst_type_schema.json#
+kind: instruction_type
+name: I
+description: I-type instructions usually have one source register, an immediate value, and one destination register
+length: 32
+opcodes:
+  funct3:
+    location: 14-12
+  opcode:
+    location: 6-0
+variables:
+  imm:
+    location: 31-20
+  rs1:
+    location: 19-15
+  rd:
+    location: 11-7