read-cache: drop unused parameter from threaded load

The load_cache_entries_threaded() function takes a src_offset parameter
that it doesn't use. This has been there since its inception in
77ff112 (read-cache: load cache entries on worker threads,
2018-10-10).

Digging on the mailing list, that parameter was part of an earlier
iteration of the series[1], but became unnecessary when the code
switched to using the IEOT extension.

[1] https://public-inbox.org/git/20180906210227.54368-5-benpeart@microsoft.com/

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Author: peff

read-cache.c

@@ -2037,7 +2037,7 @@ static void *load_cache_entries_thread(void *_data)
 }
 
 static unsigned long load_cache_entries_threaded(struct index_state *istate, const char *mmap, size_t mmap_size,
-			unsigned long src_offset, int nr_threads, struct index_entry_offset_table *ieot)
+						 int nr_threads, struct index_entry_offset_table *ieot)
 {
 	int i, offset, ieot_blocks, ieot_start, err;
 	struct load_cache_entries_thread_data *data;
@@ -2198,7 +2198,7 @@ int do_read_index(struct index_state *istate, const char *path, int must_exist)
 		ieot = read_ieot_extension(mmap, mmap_size, extension_offset);
 
 	if (ieot) {
-		src_offset += load_cache_entries_threaded(istate, mmap, mmap_size, src_offset, nr_threads, ieot);
+		src_offset += load_cache_entries_threaded(istate, mmap, mmap_size, nr_threads, ieot);
 		free(ieot);
 	} else {
 		src_offset += load_all_cache_entries(istate, mmap, mmap_size, src_offset);