powerpc/module_64: use module_init_section instead of patching names

Without this patch, module init sections are disabled by patching their
names in arch-specific code when they're loaded (which prevents code in
layout_sections from finding init sections). This patch uses the new
arch-specific module_init_section instead.

This allows modules that have .init_array sections to have the
initialisers properly called (on load, before init). Without this patch,
the initialisers are not called because .init_array is renamed to
_init_array, and thus isn't found by code in find_module_sections().

Signed-off-by: Wedson Almeida Filho <wedsonaf@google.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20220202055123.2144842-1-wedsonaf@google.com