x86: fix section mismatch warning in kernel/pci-calgary

Fix following warning:
WARNING: arch/x86/kernel/built-in.o(.text+0x1eb41): Section mismatch in reference from the function calgary_handle_quirks() to the function .init.text:calgary_set_split_completion_timeout()

calgary_handle_quirks() are only called at
__init time (in calgary_init_one() via handle_quirks ops).
So annotate this function and the sister function __init.

Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>