uek-rpm: configs: Don't set HAVE_FENTRY on OL6 builds.

uek-rpm: configs: Don't set HAVE_FENTRY on OL6 builds.

CONFIG_HAVE_FENTRY turns on a *conditional* addition of compile time
flags in the top level Makefile (-mfentry -DCC_USES_FENTRY). The OL6
stock gcc-4.4 code doesn't support this, but gcc 4.8+ does. This
changes the way function trace preambles work on the newer compilers,
which breaks kABI.

To do this effectively, the option needs to be removed from
arch/x86/Kconfig ("select HAVE_FENTRY if X86_64") so that it can be
set optionally in the RPM build configs. The OL7 configs properly
contain CONFIG_HAVE_FENTRY=y, so those will continue to build the same.

Orabug: 27509351
Signed-off-by: Todd Vierling <todd.vierling@oracle.com>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>