Blackfin: drop 4KB reserve at end of memory

The point of this small chunk was to avoid anomaly 05000310.  This never
really seemed to do what it was intended though -- no valid CPLBs exist
over the reserved memory, and there is often memory before it anyways (due
to the uClinux MTD and/or reserved DMA region).  Plus, it doesn't address
the L1 instruction case.

So drop this chunk as it wastes memory and is affront to humanity.
Signed-off-by: Barry Song <barry.song@analog.com>
Signed-off-by: Mike Frysinger <vapier@gentoo.org>

arch/blackfin/kernel/setup.c

@@ -601,11 +601,6 @@ static __init void memory_setup(void)
 	page_mask_order = get_order(3 * page_mask_nelts * sizeof(long));
 #endif
 
-#if !defined(CONFIG_MTD_UCLINUX)
-	/*In case there is no valid CPLB behind memory_end make sure we don't get to close*/
-	memory_end -= SIZE_4K;
-#endif
-
 	init_mm.start_code = (unsigned long)_stext;
 	init_mm.end_code = (unsigned long)_etext;
 	init_mm.end_data = (unsigned long)_edata;