scripts/bloat-o-meter: ignore __noinstr_text_start

scripts/bloat-o-meter: ignore __noinstr_text_start

__noinstr_text_start is adding noise to the script, ignore it.

For instance using __always_inline on __skb_incr_checksum_unnecessary and
CC=clang build.

Before this patch, __noinstr_text_start can show up and confuse us.

$ scripts/bloat-o-meter -t vmlinux.old vmlinux.new
add/remove: 0/2 grow/shrink: 3/0 up/down: 212/-206 (6)
Function                                     old     new   delta
tcp6_gro_complete                            208     283     +75
tcp4_gro_complete                            376     449     +73
__noinstr_text_start                        3536    3600     +64
__pfx___skb_incr_checksum_unnecessary         32       -     -32
__skb_incr_checksum_unnecessary              174       -    -174
Total: Before=25509464, After=25509470, chg +0.00%

After this patch we have a more precise result.

$ scripts/bloat-o-meter -t vmlinux.old vmlinux.new
add/remove: 0/2 grow/shrink: 2/0 up/down: 148/-206 (-58)
Function                                     old     new   delta
tcp6_gro_complete                            208     283     +75
tcp4_gro_complete                            376     449     +73
__pfx___skb_incr_checksum_unnecessary         32       -     -32
__skb_incr_checksum_unnecessary              174       -    -174
Total: Before=25505928, After=25505870, chg -0.00%

Link: https://lkml.kernel.org/r/20260117083448.3877418-1-edumazet@google.com
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>