[PATCH] powerpc/ps3: Fix repository.c build failure

[Thorsten Blum <thorsten.blum@linux.dev>]

GCC fails to build ps3_defconfig with the following errors:

  arch/powerpc/platforms/ps3/repository.c: In function ‘make_first_field.constprop’:
  arch/powerpc/platforms/ps3/repository.c:78:9: error: ‘strnlen’ specified bound 8 exceeds source size 3 [-Werror=stringop-overread]
     78 |         memcpy((char *)&n, text, strnlen(text, sizeof(n)));
        |         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  arch/powerpc/platforms/ps3/repository.c: In function ‘make_first_field.constprop’:
  arch/powerpc/platforms/ps3/repository.c:78:9: error: ‘strnlen’ specified bound 8 exceeds source size 4 [-Werror=stringop-overread]
     78 |         memcpy((char *)&n, text, strnlen(text, sizeof(n)));
        |         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

The current use of strnlen(text, sizeof(n)) triggers -Wstringop-overread
when text is a short string literal that is smaller than sizeof(n), such
as "bi" or "bus". Use strlen(text) instead and clamp the copy length to
sizeof(n) before memcpy().

Drop the redundant char * cast while at it.

Fixes: f94a84a09148 ("powerpc/ps3: refactor strncpy usage")
Cc: stable@vger.kernel.org
Signed-off-by: Thorsten Blum <thorsten.blum@linux.dev>
---
 arch/powerpc/platforms/ps3/repository.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/arch/powerpc/platforms/ps3/repository.c b/arch/powerpc/platforms/ps3/repository.c
index b8c030eab138..0cc755ac3e7f 100644
--- a/arch/powerpc/platforms/ps3/repository.c
+++ b/arch/powerpc/platforms/ps3/repository.c
@@ -6,6 +6,8 @@
  *  Copyright 2006 Sony Corp.
  */
 
+#include <linux/minmax.h>
+
 #include <asm/lv1call.h>
 
 #include "platform.h"
@@ -74,8 +76,9 @@ static void _dump_node(unsigned int lpar_id, u64 n1, u64 n2, u64 n3, u64 n4,
 static u64 make_first_field(const char *text, u64 index)
 {
 	u64 n = 0;
+	size_t len = min(strlen(text), sizeof(n));
 
-	memcpy((char *)&n, text, strnlen(text, sizeof(n)));
+	memcpy(&n, text, len);
 	return PS3_VENDOR_ID_NONE + (n >> 32) + index;
 }