linux-yocto/6.6: bsp/genericarm64: disable ARM64_SME

linux-yocto/6.6: bsp/genericarm64: disable ARM64_SME

Integrating the following commit(s) to linux-yocto/.:

1/1 [
    Author: Ross Burton
    Email: ross.burton@arm.com
    Subject: bsp/genericarm64: disable ARM64_SME
    Date: Thu, 21 Nov 2024 15:53:35 +0000

    From upstream:

        arm64: Kconfig: Make SME depend on BROKEN for now

        commit 81235ae0c846e1fb46a2c6fe9283fe2b2b24f7dc upstream.

        Although support for SME was merged in v5.19, we've since uncovered a
        number of issues with the implementation, including issues which might
        corrupt the FPSIMD/SVE/SME state of arbitrary tasks. While there are
        patches to address some of these issues, ongoing review has highlighted
        additional functional problems, and more time is necessary to analyse
        and fix these.

        For now, mark SME as BROKEN in the hope that we can fix things properly
        in the near future. As SME is an OPTIONAL part of ARMv9.2+, and there is
        very little extant hardware, this should not adversely affect the vast
        majority of users.

    Signed-off-by: Ross Burton <ross.burton@arm.com>
    Signed-off-by: Bruce Ashfield <bruce.ashfield@gmail.com>
]

Signed-off-by: Bruce Ashfield <bruce.ashfield@gmail.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
(cherry picked from commit 7ed7b6ad39bdab4e67acc7a5841b4519fd15a2dc)
Signed-off-by: Steve Sakoman <steve@sakoman.com>