next: arc: defconfig - gcc-9 - mmu-arcv2.h:82:2: error: implicit declaration of function 'write_aux_reg' [-Werror=implicit-function-declaration]

[Naresh Kamboju]

The following arc defconfig build warnings / errors noticed on today's
Linux next-20240326 tag.

Regressions:
    * arc - defconfig - gcc-9 build failed.

Reported-by: Linux Kernel Functional Testing <lkft@xxxxxxxxxx>

Build log:
---------
arch/arc/kernel/ptrace.c:342:16: warning: no previous prototype for
'syscall_trace_enter' [-Wmissing-prototypes]
  342 | asmlinkage int syscall_trace_enter(struct pt_regs *regs)
      |                ^~~~~~~~~~~~~~~~~~~
arch/arc/kernel/kprobes.c:193:15: warning: no previous prototype for
'arc_kprobe_handler' [-Wmissing-prototypes]
  193 | int __kprobes arc_kprobe_handler(unsigned long addr, struct
pt_regs *regs)
      |               ^~~~~~~~~~~~~~~~~~
In file included from arch/arc/include/asm/mmu.h:21,
                 from arch/arc/include/asm/pgtable.h:14,
                 from include/linux/pgtable.h:6,
                 from include/asm-generic/io.h:1047,
                 from arch/arc/include/asm/io.h:232,
                 from include/linux/io.h:13,
                 from kernel/dma/coherent.c:6:
arch/arc/include/asm/mmu-arcv2.h: In function 'mmu_setup_asid':
arch/arc/include/asm/mmu-arcv2.h:82:2: error: implicit declaration of
function 'write_aux_reg' [-Werror=implicit-function-declaration]
   82 |  write_aux_reg(ARC_REG_PID, asid | MMU_ENABLE);
      |  ^~~~~~~~~~~~~
cc1: some warnings being treated as errors

Steps to reproduce:
-------
# tuxmake --runtime podman --target-arch arc --toolchain gcc-9
--kconfig defconfig


Links:
 - https://qa-reports.linaro.org/lkft/linux-next-master/build/next-20240325/testrun/23149630/suite/build/test/gcc-9-defconfig/log
 - https://qa-reports.linaro.org/lkft/linux-next-master/build/next-20240325/testrun/23149630/suite/build/test/gcc-9-defconfig/history/
 - https://storage.tuxsuite.com/public/linaro/lkft/builds/2eA2VSZdDsL0DMBBhjoauN9IVoK/

--
Linaro LKFT
https://lkft.linaro.org