export-lora : use LLAMA_FILE_MAGIC_GGLA (#4894)

This commit replaces the magic number used in export-lora.cpp with
the one defined in llama.h, which is indirectly included via common.h.

Signed-off-by: Daniel Bevenius <daniel.bevenius@gmail.com>

examples/export-lora/export-lora.cpp

@@ -245,9 +245,8 @@ static struct lora_data * load_lora(struct lora_info * info) {
     params_ggml.no_alloc   = true;
     result->ctx = ggml_init(params_ggml);
 
-    uint32_t LLAMA_FILE_MAGIC_LORA = 0x67676C61; // 'ggla'
     uint32_t magic   = file.read_u32();
-    if (magic != LLAMA_FILE_MAGIC_LORA) {
+    if (magic != LLAMA_FILE_MAGIC_GGLA) {
         die_fmt("unexpected lora header file magic in '%s'", info->filename.c_str());
     }
     uint32_t version = file.read_u32();