dt-bindings: riscv: document zicfilp and zicfiss in extensions.yaml

dt-bindings: riscv: document zicfilp and zicfiss in extensions.yaml

Make an entry for cfi extensions in extensions.yaml.

Signed-off-by: Deepak Gupta <debug@rivosinc.com>
Acked-by: Rob Herring (Arm) <robh@kernel.org>
Tested-by: Andreas Korb <andreas.korb@aisec.fraunhofer.de> # QEMU, custom CVA6
Tested-by: Valentin Haudiquet <valentin.haudiquet@canonical.com>
Link: https://patch.msgid.link/20251112-v5_user_cfi_series-v23-2-b55691eacf4f@rivosinc.com
[pjw@kernel.org: updated subject]
Signed-off-by: Paul Walmsley <pjw@kernel.org>