hdl: nios: add -DNUAND_MODIFICATIONS

bladeRF_nios needs NUAND_MODIFICATIONS to pick up local mods in
libad936x header files.

Author: rtucker

hdl/fpga/platforms/common/bladerf/software/bladeRF_nios/Makefile

@@ -189,7 +189,7 @@ CREATE_ELF_DERIVED_FILES := 0
 CREATE_LINKER_MAP := 1
 
 # Common arguments for ALT_CFLAGSs
-APP_CFLAGS_DEFINED_SYMBOLS :=
+APP_CFLAGS_DEFINED_SYMBOLS := -DNUAND_MODIFICATIONS
 APP_CFLAGS_UNDEFINED_SYMBOLS :=
 APP_CFLAGS_OPTIMIZATION := -Os -fshort-enums
 APP_CFLAGS_DEBUG_LEVEL := -g