ARM: zynq: make use of debug_ll_io_init()

Convert low-level debugging routines to make use of debug_ll_io_init().
This is part of the preparation for ARCH_MULTIPLATFORM support for Zynq.

Signed-off-by: Josh Cartwright <josh.cartwright@ni.com>
Tested-by: Michal Simek <michal.simek@xilinx.com>

arch/arm/Kconfig.debug

@@ -435,6 +435,7 @@ config DEBUG_LL_INCLUDE
 	default "debug/socfpga.S" if DEBUG_SOCFPGA_UART
 	default "debug/vexpress.S" if DEBUG_VEXPRESS_UART0_DETECT || \
 		DEBUG_VEXPRESS_UART0_CA9 || DEBUG_VEXPRESS_UART0_RS1
+	default "debug/zynq.S" if DEBUG_ZYNQ_UART0 || DEBUG_ZYNQ_UART1
 	default "mach/debug-macro.S"
 
 config EARLY_PRINTK