dm: close filepointer before exiting acrn_load_elf()

In acrn_load_elf(), file pointer 'fp' is kept in
 open state before exiting if 'load_elf32()' is executed,
 this patch is to fix this bug.

Tracked-On: #3817
Signed-off-by: Yonghua Huang <yonghua.huang@intel.com>

devicemodel/core/sw_load_elf.c

@@ -243,6 +243,7 @@ acrn_load_elf(struct vmctx *ctx, char *elf_file_name, unsigned long *entry,
 	}
 
 	*entry = elf_ehdr->e_entry;
+	fclose(fp);
 	free(elf_buf);
 
 	return ret;