arm: add mach-nexell (all files except header files)

Changes in relation to FriendlyARM's U-Boot nanopi2-v2016.01:
- SPL not supported yet --> no spl-directory in arch/arm/mach-nexell.
  Appropriate line in Makefile removed.
- clock.c: 'section(".data")' added to declaration of clk_periphs[] and
  core_hz.
- Kconfig: Changes to have a structure like in mach-bcm283x/Kconfig,
  e.g. "config ..." entries moved from other Kconfig.
- timer.c: 'section(".data")' added to declaration of timestamp and
  lastdec.
- arch/arm/mach-nexell/serial.c removed because this is for the UARTs
  of the S5P6818 SoC which is not supported yet. S5P4418 UARTs are
  different, here the (existing) PL011-code is used.
- '#ifdef CONFIG...' changed to 'if (IS_ENABLED(CONFIG...))' where
  possible (and similar).

Signed-off-by: Stefan Bosch <stefan_b@posteo.net>
diff --git a/arch/arm/mach-nexell/reset.c b/arch/arm/mach-nexell/reset.c
new file mode 100644
index 0000000..1f732a3
--- /dev/null
+++ b/arch/arm/mach-nexell/reset.c
@@ -0,0 +1,33 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * (C) Copyright 2016 Nexell
+ * Youngbok, Park <park@nexell.co.kr>
+ */
+
+/*
+ *FIXME : Not support device tree & reset control driver.
+ *        will remove after support device tree & reset control driver.
+ */
+#include <common.h>
+#include <asm/io.h>
+#include <asm/arch/nexell.h>
+#include <asm/arch/reset.h>
+
+struct	nx_rstcon_registerset {
+	u32	regrst[(NUMBER_OF_RESET_MODULE_PIN + 31) >> 5];
+};
+
+static struct nx_rstcon_registerset *nx_rstcon =
+			(struct nx_rstcon_registerset *)PHY_BASEADDR_RSTCON;
+
+void nx_rstcon_setrst(u32 rstindex, enum rstcon status)
+{
+	u32 regnum, bitpos, curstat;
+
+	regnum		= rstindex >> 5;
+	curstat		= (u32)readl(&nx_rstcon->regrst[regnum]);
+	bitpos		= rstindex & 0x1f;
+	curstat		&= ~(1UL << bitpos);
+	curstat		|= (status & 0x01) << bitpos;
+	writel(curstat, &nx_rstcon->regrst[regnum]);
+}