powerpc: rename powerpc_debugfs_root to arch_debugfs_dir

No functional change in this patch. arch_debugfs_dir is the generic kernel
name declared in linux/debugfs.h for arch-specific debugfs directory.
Architectures like x86/s390 already use the name. Rename powerpc
specific powerpc_debugfs_root to arch_debugfs_dir.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210812132831.233794-2-aneesh.kumar@linux.ibm.com

diff --git a/arch/powerpc/kernel/eeh_cache.c b/arch/powerpc/kernel/eeh_cache.c
index bf32704..9bdaaf7 100644
--- a/arch/powerpc/kernel/eeh_cache.c
+++ b/arch/powerpc/kernel/eeh_cache.c
@@ -12,8 +12,8 @@
 #include <linux/slab.h>
 #include <linux/spinlock.h>
 #include <linux/atomic.h>
+#include <linux/debugfs.h>
 #include <asm/pci-bridge.h>
-#include <asm/debugfs.h>
 #include <asm/ppc-pci.h>
 
 
@@ -283,6 +283,6 @@ DEFINE_SHOW_ATTRIBUTE(eeh_addr_cache);
 void eeh_cache_debugfs_init(void)
 {
 	debugfs_create_file_unsafe("eeh_address_cache", 0400,
-			powerpc_debugfs_root, NULL,
+			arch_debugfs_dir, NULL,
 			&eeh_addr_cache_fops);
 }