m68k: sun3x: Do not mark dvma_map_iommu() inline

dvma_map_iommu() is called from the common Sun3/3x DVMA management code,
but never from inside arch/m68k/sun3x/dvma.c.  Hence it does not make
sense to mark it inline.

Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Link: https://lore.kernel.org/r/0884fd1f5d6775535bf20b13cc74283df4955e49.1694613528.git.geert@linux-m68k.org