bootm: fix size arg of flush_cache() in bootm_load_os().

Variable _load_end_ points to end address of uncompressed buffer
(*not* uncomress_buffer_end / sizeof(ulong)), so multipling uncompressed
size with sizeof(ulong) is grossly incorrect in flush_cache().
It might lead to access of address beyond valid memory range and hang the CPU.

Tested on MIPS architecture by using compressed(gzip, lzma)
and uncompressed uImage.

Signed-off-by: Purna Chandra Mandal <purna.mandal@microchip.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Daniel Schwierzeck <daniel.schwierzeck@gmail.com>

common/bootm.c

@@ -435,7 +435,7 @@ static int bootm_load_os(bootm_headers_t *images, unsigned long *load_end,
 		bootstage_error(BOOTSTAGE_ID_DECOMP_IMAGE);
 		return err;
 	}
-	flush_cache(load, (*load_end - load) * sizeof(ulong));
+	flush_cache(load, *load_end - load);
 
 	debug("   kernel loaded at 0x%08lx, end = 0x%08lx\n", load, *load_end);
 	bootstage_mark(BOOTSTAGE_ID_KERNEL_LOADED);