s390/setup: remove obsolete #ifdef

The #ifdef CONFIG_DMA_API_DEBUG check in reserve_kernel() is no longer
needed, since commit ea535e41 ("dma-debug: switch check from _text
to _stext") changed the logic in lib/dma-debug.c, so remove it.
Reviewed-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Gerald Schaefer <gerald.schaefer@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

arch/s390/kernel/setup.c

@@ -795,18 +795,9 @@ static void __init reserve_kernel(void)
 {
 	unsigned long start_pfn = PFN_UP(__pa(_end));
 
-#ifdef CONFIG_DMA_API_DEBUG
-	/*
-	 * DMA_API_DEBUG code stumbles over addresses from the
-	 * range [PARMAREA_END, _stext]. Mark the memory as reserved
-	 * so it is not used for CONFIG_DMA_API_DEBUG=y.
-	 */
-	memblock_reserve(0, PFN_PHYS(start_pfn));
-#else
 	memblock_reserve(0, PARMAREA_END);
 	memblock_reserve((unsigned long)_stext, PFN_PHYS(start_pfn)
 			 - (unsigned long)_stext);
-#endif
 }
 
 static void __init setup_memory(void)