buildman size check doesn't fully understand rodata

When moving the long help text from "data" to "rodata" (by marking it as const), I see:

            thunderx_88xx  : all -2 data -3928 rodata +3926
               u-boot: add: 0/-6, grow: 0/0 bytes: 0/-3926 (-3926)
                 function                                   old     new   delta
                 source_help_text                            40       -     -40
                 imgextract_help_text                        85       -     -85
                 env_help_text                              330       -    -330
                 booti_help_text                            728       -    -728
                 bootm_help_text                            910       -    -910
                 fdt_help_text                             1833       -   -1833

Which is mostly, but not entirely right. If we build by hand and examine u-boot.map we see:

 .rodata.fdt_help_text
                0x000000000052411e      0x729 cmd/fdt.o

Which is what's expected. It seems that examining the rodata section is missing from the bloat-related options, in some cases.