powerpc/xive: Do not mark xive_request_ipi() as __init

Compiling ppc64le_defconfig with clang-14 shows a modpost warning:

WARNING: modpost: vmlinux.o(.text+0xa74e0): Section mismatch in
reference from the function xive_setup_cpu_ipi() to the function
.init.text:xive_request_ipi()
The function xive_setup_cpu_ipi() references
the function __init xive_request_ipi().
This is often because xive_setup_cpu_ipi lacks a __init
annotation or the annotation of xive_request_ipi is wrong.

xive_request_ipi() is called from xive_setup_cpu_ipi(), which is not
__init, so xive_request_ipi() should not be marked __init. Remove the
attribute so there is no more warning.

Fixes: cbc06f05

 ("powerpc/xive: Do not skip CPU-less nodes when creating the IPIs")
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210816185711.21563-1-nathan@kernel.org