arch/z80/src/ez80/Toolchain.defs: Correct some CFLAGS when optimization suppressed.
arch/z80/src/ez80/Kconfig arch/z80/src/ez80/ez80_emac.c: Remove configuration option for selecting EMAC RAM address. This is duplicated and possibly conflicting. The correct address for the RAM is provided in the linker command file. The RAM should be configured once and using this single definitions.
arch/z80/src/ez80/ez80_startup.asm and arch/z80/src/ez80/ez80f9*_init.asm. Move RAM and FLAH intialization out of MCU-specific logic to common start-up logic. We cannot call any functions until SRAM is initialized and the stack is properly initialized because the return address is stored on the stack. Use internal SRAM for the IDLE stack to avoid the chicken'n'egg problem.
boards/z80/ez80/z20x/configs/sdboot/sdboot.zdsproj: Discuss build environments.
