x86: Deinline dma_free_attrs()

Reduces kernel size by 76720 bytes on allyesconfig build:

    text     data      bss       dec     hex filename
82594029 22255352 20627456 125476837 77a9fe5 vmlinux1
82517277 22255384 20627456 125400117 7797435 vmlinux2

Signed-off-by: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Don Dutile <ddutile@redhat.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: x86@kernel.org
Link: http://lkml.kernel.org/r/1428926075-28796-3-git-send-email-dvlasenk@redhat.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>