The debug definitions were missing for MACH_JZ4770, resulting in a build
failure when DEBUG_ZBOOT was set.
Since the UART addresses are the same across all Ingenic SoCs, we just
use a #ifdef CONFIG_MACH_INGENIC instead of checking for individual
Ingenic SoCs.
Additionally, I added a #define for the UART0 address in-code and
dropped the <asm/mach-jz4740/base.h> include, for the reason that this
include file is slowly being phased out as the whole platform is being
moved to devicetree.