perf kbuild: remove legacy libgtk2-related build variables

Remove NO_GTK2 (replaced by CONFIG_LIBGTK2 or CONFIG_GTK2)
Remove HAVE_GTK2_SUPPORT from CFLAGS (replaced by CONFIG_LIBGTK2)
Remove HAVE_GTK_INFO_BAR_SUPPORT from CFLAGS (replaced by
CONFIG_LIBGTK2_INFOBAR)
perf kbuild: remove legacy libperl-related build variables

Remove NO_LIBPERL (replaced by CONFIG_LIBPERL)
perf kbuild: remove legacy timerfd-related build variable

Remove HAVE_TIMERFD_SUPPORT (replaced by CONFIG_TIMERFD)