pylance: carry riscv64 SIMD fallback patch forward to 12.0.0

The build-pylance.yml checkout unconditionally applies
patches/pylance/${PYLANCE_VERSION}/0001*.patch, but the 11.0.0 patch
directory was never copied forward when 12.0.0 was added, so
"Build pylance 12.0.0 cp310-abi3-manylinux_riscv64" failed at
`git apply` with "No such file or directory" before any build step ran.

lance-linalg's f32x8/f32x16/i32x8/f64x4/f64x8 SIMD types still hardcode
x86_64/aarch64/loongarch64 with no riscv64 fallback at v12.0.0, same as
at v11.0.0, and the existing patch applies cleanly to the v12.0.0
checkout (git apply reports only line-number offsets, no conflicts) -
so the same patch content is carried forward verbatim, matching the
scipy/ddtrace precedent of an unchanged patch reused across versions.

Author: luhenry