ARM: zynq: add support for ARCH_MULTIPLATFORM

The majority of changes are necessary to remove dependencies on header
files within arch/arm/mach-zynq/include/mach:

  uncompress.h
    - Deleted. It is unused for ARCH_MULTIPLATFORM builds.

  uart.h:
    - Move uart definitions out of uart.h into debug/zynq.S, which is
      now the only user

  zynq_soc.h:
    - Move SCU address definitions into common.c.
    - Other #defines, such as PERIPHERAL_CLOCK_RATE, TTC0_BASE, etc, are
      unused and can be dropped

Signed-off-by: Josh Cartwright <josh.cartwright@ni.com>
Tested-by: Michal Simek <michal.simek@xilinx.com>
diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index ccfe0ab..28a2048 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -955,18 +955,6 @@
 	help
 	  Support for VIA/WonderMedia VT8500/WM85xx System-on-Chip.
 
-config ARCH_ZYNQ
-	bool "Xilinx Zynq ARM Cortex A9 Platform"
-	select ARM_AMBA
-	select ARM_GIC
-	select COMMON_CLK
-	select CPU_V7
-	select GENERIC_CLOCKEVENTS
-	select ICST
-	select MIGHT_HAVE_CACHE_L2X0
-	select USE_OF
-	help
-	  Support for Xilinx Zynq ARM Cortex A9 Platform
 endchoice
 
 menu "Multiple platform selection"
@@ -1128,6 +1116,8 @@
 
 source "arch/arm/mach-w90x900/Kconfig"
 
+source "arch/arm/mach-zynq/Kconfig"
+
 # Definitions to make life easier
 config ARCH_ACORN
 	bool