arm: zynq: Remove checkboard and enable DISPLAY_CPUINFO

Now that showing silicon version is part of the CPU
info display, let's remove checkboard().

Note that the generic show_board_info() will still
show the DT 'model' property. For instance:

U-Boot 2018.05-rc2-00025-g611b3ee0159b (Apr 19 2018 - 11:23:12 +0200)

CPU:   Zynq 7z045
Silicon: v1.0
Model: Zynq ZC706 Development Board
I2C:   ready

Based on patches from Ariel D'Alessandro <ariel@vanguardiasur.com.ar>,
and Ezequiel Garcia <ezequiel@vanguardiasur.com.ar>

mini configuration doesn't need to show this information.

Signed-off-by: Michal Simek <michal.simek@xilinx.com>
diff --git a/arch/arm/mach-zynq/cpu.c b/arch/arm/mach-zynq/cpu.c
index 7853785..a3422cd 100644
--- a/arch/arm/mach-zynq/cpu.c
+++ b/arch/arm/mach-zynq/cpu.c
@@ -123,3 +123,22 @@
 	return 0;
 }
 #endif
+
+#ifdef CONFIG_DISPLAY_CPUINFO
+int print_cpuinfo(void)
+{
+	u32 version;
+	int cpu_id = cpu_desc_id();
+
+	if (cpu_id < 0)
+		return 0;
+
+	version = zynq_get_silicon_version() << 1;
+	if (version > (PCW_SILICON_VERSION_3 << 1))
+		version += 1;
+
+	printf("CPU:   Zynq %s\n", zynq_fpga_descs[cpu_id].devicename);
+	printf("Silicon: v%d.%d\n", version >> 1, version & 1);
+	return 0;
+}
+#endif