add a few optional BRs for perf

This enables a few optional perf features that looked like accidentally left off; I don't care about those, just noticed below warnings in the log decided to just submit this MR; if there are any strong reasons why some or all of those are off, just let me know, then I will drop or modify the MR.

Makefile.config:593: No elfutils/debuginfod.h found, no debuginfo server support, please install libdebuginfod-dev/elfutils-debuginfod-client-devel or equivalent
Makefile.config:1112: No libcapstone found, disables disasm engine support for 'perf script', please install libcapstone-dev/capstone-devel
Makefile.config:1174: libpfm4 not found, disables libpfm4 support. Please install libpfm-devel or libpfm4-dev

Signed-off-by: Thorsten Leemhuis fedora@leemhuis.info