efi_loader: new function efi_memcpy_runtime()

Provide a memcpy() function that we can use at UEFI runtime.

Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
diff --git a/lib/efi_loader/efi_runtime.c b/lib/efi_loader/efi_runtime.c
index a4aa1d8..5b6506f 100644
--- a/lib/efi_loader/efi_runtime.c
+++ b/lib/efi_loader/efi_runtime.c
@@ -138,6 +138,25 @@
 }
 
 /**
+ * efi_memcpy_runtime() - copy memory area
+ *
+ * At runtime memcpy() is not available.
+ *
+ * @dest:	destination buffer
+ * @src:	source buffer
+ * @n:		number of bytes to copy
+ * Return:	pointer to destination buffer
+ */
+void __efi_runtime efi_memcpy_runtime(void *dest, const void *src, size_t n)
+{
+	u8 *d = dest;
+	const u8 *s = src;
+
+	for (; n; --n)
+		*d++ = *s++;
+}
+
+/**
  * efi_update_table_header_crc32() - Update crc32 in table header
  *
  * @table:	EFI table