um: Fix to call read_initrd after init_bootmem

um: Fix to call read_initrd after init_bootmem

commit 5b4236e17cc1bd9fa14b2b0c7a4ae632d41f2e20 upstream.

Since read_initrd() invokes alloc_bootmem() for allocating
memory to load initrd image, it must be called after init_bootmem.

This makes read_initrd() called directly from setup_arch()
after init_bootmem() and mem_total_pages().

Fixes: b63236972e1 ("um: Setup physical memory in setup_arch()")
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Richard Weinberger <richard@nod.at>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>