Improper use of #elif to test if an address is defined (breaks axidma tests in normal config)

Most of the dma test examples have a block that looks something like this

#ifdef XPAR_AXI_7SDDR_0_S_AXI_BASEADDR
#define DDR_BASE_ADDR		XPAR_AXI_7SDDR_0_S_AXI_BASEADDR
#elif XPAR_MIG7SERIES_0_BASEADDR
#define DDR_BASE_ADDR	XPAR_MIG7SERIES_0_BASEADDR
#elif XPAR_MIG_0_BASEADDR
#define DDR_BASE_ADDR	XPAR_MIG_0_BASEADDR
#elif XPAR_PSU_DDR_0_S_AXI_BASEADDR
#define DDR_BASE_ADDR	XPAR_PSU_DDR_0_S_AXI_BASEADDR
#endif

The problem is that while the first preprocessor test is using an #ifdef the else statements check for a truth instead of an define. In many cases the base address will be 0 for XPAR_PSU_DDR_0_S_AXI_BASEADDR so the build results in a warning and picks a poor choice for the address. This bug is not just in the dma code, and #elif code that checks for an address should be using defined like this #elif defined(XPAR_PSU_DDR_0_S_AXI_BASEADDR)

Example here
https://github.com/Xilinx/embeddedsw/blob/fb647e6b4c00f5154eba52a88b948195b6f1dc2b/XilinxProcessorIPLib/drivers/axidma/examples/xaxidma_example_sg_poll.c#L110

Start with XilinxProcessorIPLib/drivers/axidma/examples/xaxidma_example_sg_poll.c around line 110, then search the repository for similar #elif checks involving address macros. Confirm each conditional tests whether the macro is defined, and verify the affected DMA examples build without the reported warning.