MIPS: Fix build with DEBUG_ZBOOT and MACH_JZ4770

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.

Fixes: 9be5f3e9 ("MIPS: ingenic: Initial JZ4770 support")
Signed-off-by: Paul Cercueil <paul@crapouillou.net>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: linux-mips@linux-mips.org
Cc: <stable@vger.kernel.org> # 4.16
Patchwork: https://patchwork.linux-mips.org/patch/18957/


Signed-off-by: James Hogan <jhogan@kernel.org>