RISC-V: Add fragmented config for debug options

euleros inclusion
category: feature
feature: initial KVM RISC-V support
bugzilla: 46845
CVE: NA

Various Linux kernel DEBUG options have big performance impact so
these should not be enabled in RISC-V normal defconfigs.

Instead we should have separate RISC-V fragmented config for enabling
these DEBUG options. This way Linux RISC-V kernel can be built for
both non-debug and debug purposes using same defconfig.

This patch moves additional DEBUG options to extra_debug.config.

To configure a non-debug RV64 kernel, we use our normal defconfig:
   $ make O=<linux_build_directory> defconfig
Wherease to configure a debug RV64 kernel, we use extra_debug.config:
   $ make O=<linux_build_directory> defconfig extra_debug.config

Reference: https://gitee.com/openeuler/kernel/issues/I26X9V


Signed-off-by: Anup Patel <anup.patel@wdc.com>
Reviewed-by: Yifei Jiang <jiangyifei@huawei.com>
Acked-by: Xie XiuQi <xiexiuqi@huawei.com>
Signed-off-by: Chen Jun <chenjun102@huawei.com>