[PATCH v2] Only call ppc_md.setup_arch() if it is provided.

[Grant Likely <grant.likely@secretlab.ca>]

From: Grant Likely <grant.likely@secretlab.ca>

This allows platforms which don't have anything to do at setup_arch time
(like a bunch of the 4xx platforms) to eliminate an empty setup_arch hook.

Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
---

 arch/powerpc/kernel/setup_32.c |    3 ++-
 arch/powerpc/kernel/setup_64.c |    3 ++-
 include/asm-powerpc/machdep.h  |    2 +-
 3 files changed, 5 insertions(+), 3 deletions(-)

diff --git a/arch/powerpc/kernel/setup_32.c b/arch/powerpc/kernel/setup_32.c
index 7474502..cd870a8 100644
--- a/arch/powerpc/kernel/setup_32.c
+++ b/arch/powerpc/kernel/setup_32.c
@@ -290,7 +290,8 @@ void __init setup_arch(char **cmdline_p)
 	conswitchp = &dummy_con;
 #endif
 
-	ppc_md.setup_arch();
+	if (ppc_md.setup_arch)
+		ppc_md.setup_arch();
 	if ( ppc_md.progress ) ppc_md.progress("arch: exit", 0x3eab);
 
 	paging_init();
diff --git a/arch/powerpc/kernel/setup_64.c b/arch/powerpc/kernel/setup_64.c
index 3089eae..008ab68 100644
--- a/arch/powerpc/kernel/setup_64.c
+++ b/arch/powerpc/kernel/setup_64.c
@@ -530,7 +530,8 @@ void __init setup_arch(char **cmdline_p)
 	conswitchp = &dummy_con;
 #endif
 
-	ppc_md.setup_arch();
+	if (ppc_md.setup_arch)
+		ppc_md.setup_arch();
 
 	paging_init();
 	ppc64_boot_msg(0x15, "Setup Done");
diff --git a/include/asm-powerpc/machdep.h b/include/asm-powerpc/machdep.h
index 71c6e7e..cc7c17f 100644
--- a/include/asm-powerpc/machdep.h
+++ b/include/asm-powerpc/machdep.h
@@ -99,7 +99,7 @@ struct machdep_calls {
 #endif /* CONFIG_PPC64 */
 
 	int		(*probe)(void);
-	void		(*setup_arch)(void);
+	void		(*setup_arch)(void); /* Optional, may be NULL */
 	void		(*init_early)(void);
 	/* Optional, may be NULL. */
 	void		(*show_cpuinfo)(struct seq_file *m);