ARM: 8949/1: mm: mark free_memmap as __init

As of commit ac7c3e4f ("compiler: enable CONFIG_OPTIMIZE_INLINING
forcibly"), free_memmap() might not always be inlined, and thus is
triggering a section warning:

WARNING: vmlinux.o(.text.unlikely+0x904): Section mismatch in reference from the function free_memmap() to the function .meminit.text:memblock_free()

Mark it as __init, since the faller (free_unused_memmap) already is.

Fixes: ac7c3e4f

 ("compiler: enable CONFIG_OPTIMIZE_INLINING forcibly")
Signed-off-by: Olof Johansson <olof@lixom.net>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>