scripts/recordmcount.{c,pl}: support -ffunction-sections .text.* section names

scripts/recordmcount.{c,pl}: support -ffunction-sections .text.* section names

When building with -ffunction-sections, the compiler will place each
function into its own ELF section, prefixed with ".text".  For example,
a simple test module with functions test_module_do_work() and
test_module_wq_func():

  % objdump --section-headers test_module.o | awk '/\.text/{print $2}'
  .text
  .text.test_module_do_work
  .text.test_module_wq_func
  .init.text
  .exit.text

Adjust the recordmcount scripts to look for ".text" as a section name
prefix.  This will ensure that those functions will be included in the
__mcount_loc relocations:

  % objdump --reloc --section __mcount_loc test_module.o
  OFFSET           TYPE              VALUE
  0000000000000000 R_X86_64_64       .text.test_module_do_work
  0000000000000008 R_X86_64_64       .text.test_module_wq_func
  0000000000000010 R_X86_64_64       .init.text

Link: http://lkml.kernel.org/r/1542745158-25392-2-git-send-email-joe.lawrence@redhat.com
Signed-off-by: Joe Lawrence <joe.lawrence@redhat.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>