linux-user/elfload.c: Correct SME feature names reported in cpuinfo

linux-user/elfload.c: Correct SME feature names reported in cpuinfo

Some of the names we use for CPU features in linux-user's dummy
/proc/cpuinfo don't match the strings in the real kernel in
arch/arm64/kernel/cpuinfo.c. Specifically, the SME related
features have an underscore in the HWCAP_FOO define name,
but (like the SVE ones) they do not have an underscore in the
string in cpuinfo. Correct the errors.

Fixes: a55b9e7226708 ("linux-user: Emulate /proc/cpuinfo on aarch64 and arm")
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>