scripts/gdb: raise error with reduced debugging information

scripts/gdb: raise error with reduced debugging information

If CONFIG_DEBUG_INFO_REDUCED is enabled in the kernel configuration, we
will typically not be able to load vmlinux-gdb.py and will fail with:

Traceback (most recent call last):
  File "/home/fainelli/work/buildroot/output/arm64/build/linux-custom/vmlinux-gdb.py", line 25, in <module>
    import linux.utils
  File "/home/fainelli/work/buildroot/output/arm64/build/linux-custom/scripts/gdb/linux/utils.py", line 131, in <module>
    atomic_long_counter_offset = atomic_long_type.get_type()['counter'].bitpos
KeyError: 'counter'

Rather be left wondering what is happening only to find out that reduced
debug information is the cause, raise an eror.  This was not typically a
problem until e3c8d33e0d62 ("scripts/gdb: fix 'lx-dmesg' on 32 bits arch")
but it has since then.

Link: https://lkml.kernel.org/r/[email protected]
Fixes: e3c8d33e0d62 ("scripts/gdb: fix 'lx-dmesg' on 32 bits arch")
Signed-off-by: Florian Fainelli <[email protected]>
Cc: Antonio Borneo <[email protected]>
Cc: Jan Kiszka <[email protected]>
Cc: John Ogness <[email protected]>
Cc: Kieran Bingham <[email protected]>
Cc: Petr Mladek <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>