scripts/bloat-o-meter: ignore _sdata

scripts/bloat-o-meter: ignore _sdata

_sdata is a linker symbol, but bloat-o-meter may consider it as a real
variable:

$ scripts/bloat-o-meter vmlinux.orig vmlinux
add/remove: 7/1 grow/shrink: 0/0 up/down: 3437/-4096 (-659)
Function                                     old     new   delta
crc32table_le                                  -    1024   +1024
crc32table_be                                  -    1024   +1024
crc32ctable_le                                 -    1024   +1024
byte_rev_table                                 -     256    +256
crc32_be                                       -      39     +39
crc32c                                         -      35     +35
crc32_le                                       -      35     +35
_sdata                                      4096       -   -4096
Total: Before=8592564398, After=8592563739, chg -0.00%

With the patch:

$ scripts/bloat-o-meter vmlinux.orig vmlinux
add/remove: 7/0 grow/shrink: 0/0 up/down: 3437/0 (3437)
Function                                     old     new   delta
crc32table_le                                  -    1024   +1024
crc32table_be                                  -    1024   +1024
crc32ctable_le                                 -    1024   +1024
byte_rev_table                                 -     256    +256
crc32_be                                       -      39     +39
crc32c                                         -      35     +35
crc32_le                                       -      35     +35
Total: Before=8592560302, After=8592563739, chg +0.00%

Link: https://lore.kernel.org/20260504203606.427972-1-ynorov@nvidia.com
Signed-off-by: Yury Norov <ynorov@nvidia.com>
Cc: Valtteri Koskivuori <vkoskiv@gmail.com>
Cc: Eric Dumazet <edumazet@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>