powerpc/pasemi: mark pas_shutdown() static

Allmodconfig builds show a warning about one function that is accidentally
marked global:

arch/powerpc/platforms/pasemi/setup.c:67:6: error: no previous prototype for 'pas_shutdown' [-Werror=missing-prototypes]

Fixes: 656fdf3a ("powerpc/pasemi: Add Nemo board device init code.")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20231108125843.3806765-19-arnd@kernel.org

arch/powerpc/platforms/pasemi/setup.c

@@ -64,7 +64,7 @@ static void __noreturn pas_restart(char *cmd)
 }
 
 #ifdef CONFIG_PPC_PASEMI_NEMO
-void pas_shutdown(void)
+static void pas_shutdown(void)
 {
 	/* Set the PLD bit that makes the SB600 think the power button is being pressed */
 	void __iomem *pld_map = ioremap(0xf5000000,4096);