[PATCH] efi/libstub: add strrchr function

[Rob Herring <robh@kernel.org>]

libfdt gained a new dependency on strrchr, so copy the implementation
from lib/string.c.

Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Rob Herring <robh@kernel.org>
---
Please ack. This is a dependency for dtc/libfdt sync with upstream.

 drivers/firmware/efi/libstub/string.c | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)

diff --git a/drivers/firmware/efi/libstub/string.c b/drivers/firmware/efi/libstub/string.c
index ed10e3f602c5..c1a7e58a5af7 100644
--- a/drivers/firmware/efi/libstub/string.c
+++ b/drivers/firmware/efi/libstub/string.c
@@ -56,3 +56,20 @@ int strncmp(const char *cs, const char *ct, size_t count)
 	return 0;
 }
 #endif
+
+#ifndef __HAVE_ARCH_STRRCHR
+/**
+ * strrchr - Find the last occurrence of a character in a string
+ * @s: The string to be searched
+ * @c: The character to search for
+ */
+char *strrchr(const char *s, int c)
+{
+	const char *last = NULL;
+	do {
+		if (*s == (char)c)
+			last = s;
+	} while (*s++);
+	return (char *)last;
+}
+#endif
-- 
2.14.1