kernel.bbclass: Add force flag to rm calls

kernel.bbclass: Add force flag to rm calls

The latest 6.5 kernels do not appear to create the source file in
${D}${nonarch_base_libdir}/modules/${KERNEL_VERSION}/source so the
recipe errors out when trying to remove it.  Simple fix is to add the
-f (force) flag to the call.

Signed-off-by: Ryan Eatmon <reatmon@ti.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
(cherry picked from commit 2e669bf797b15d803e7d6a700e449bdc467a4bcc)
Signed-off-by: Steve Sakoman <steve@sakoman.com>