m68k: sun3: Make print_pte() static

When building with W=1:

    arch/m68k/sun3/mmu_emu.c:70:6: warning: no previous prototype for ‘print_pte’ [-Wmissing-prototypes]
       70 | void print_pte (pte_t pte)
	  |      ^~~~~~~~~

Fix this by making print_pte() static.
There was never a user outside arch/m68k/sun3/mmu_emu.c.

Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Link: https://lore.kernel.org/r/a56c70e85584efb3681cb7e94aff167299dfa5e4.1694613528.git.geert@linux-m68k.org