contrib/plugins/execlog.c: warning: passing argument 2 of ‘g_ptr_array_add’ discards ‘const’ qualifier from pointer target type [-Wdiscarded-qualifiers]

Description of problem

Hit some warning messages when compiling upstream qemu

Steps to reproduce

1. Clone repo and compile it

1.1 git clone https://gitlab.com/qemu-project/qemu.git

1.2 mkdir build

1.3 cd build/

1.4 ../configure --target-list=x86_64-softmmu --enable-debug-info

1.5 make

2. It will print the following warning messages:

[2767/2767] Linking target tests/qtest/netdev-socket
/root/qemu/contrib/plugins/execlog.c: In function ‘registers_init’:
/root/qemu/contrib/plugins/execlog.c:339:63: warning: passing argument 2 of ‘g_ptr_array_add’ discards ‘const’ qualifier from pointer target type [-Wdiscarded-qualifiers]
  339 |                             g_ptr_array_add(all_reg_names, reg->name);
      |                                                            ~~~^~~~~~
In file included from /usr/include/glib-2.0/glib.h:31,
                 from /root/qemu/contrib/plugins/execlog.c:9:
/usr/include/glib-2.0/glib/garray.h:192:62: note: expected ‘gpointer’ {aka ‘void *’} but argument is of type ‘const char *’
  192 |                                            gpointer          data);
      |                                            ~~~~~~~~~~~~~~~~~~^~~~

Additional information

1. After Eugenio Perez Martin (eperezma@redhat.com) debug, we found this problem introduced by this commit:

commit af6e4e0a22c18a7cc97650caec56ed99c9899dd7
Author: Alex Bennée <alex.bennee@linaro.org>
Date:   Tue Feb 27 14:43:32 2024 +0000

    contrib/plugins: extend execlog to track register changes

2. The latest commit in my env:

commit db596ae19040574e41d086e78469014191d7d7fc (origin/staging, origin/master, origin/HEAD)
Merge: 7d4e29ef80 7558300c53
Author: Peter Maydell <peter.maydell@linaro.org>
Date:   Tue Mar 5 13:54:54 2024 +0000

    Merge tag 'pull-target-arm-20240305' of https://git.linaro.org/people/pmaydell/qemu-arm into staging
    
    target-arm queue:
     * raspi: Implement Broadcom Serial Controller (BSC) for BCM2835 boards
     * hw/char/pl011: Add support for loopback
     * STM32L4x5: Implement RCC clock control device
     * target/arm: Do memory type alignment checks
     * atomic.h: Reword confusing comment for qatomic_cmpxchg
     * qemu-options.hx: Don't claim "-serial" has limit of 4 serial ports