ARMv7 may not support Generic Timer Extension

If ARMv7 based platform does not set ARM_CORTEX_Ax=yes, platform
shall define ARMV7_SUPPORTS_GENERIC_TIMER to enable generic timer
support.
Signed-off-by: Etienne Carriere <etienne.carriere@linaro.org>

lib/psci/psci_setup.c

@@ -266,8 +266,10 @@ int psci_setup(const psci_lib_args_t *lib_args)
  ******************************************************************************/
 void psci_arch_setup(void)
 {
+#if ARM_ARCH_MAJOR > 7 || defined(ARMV7_SUPPORTS_GENERIC_TIMER)
 	/* Program the counter frequency */
 	write_cntfrq_el0(plat_get_syscnt_freq2());
+#endif
 
 	/* Initialize the cpu_ops pointer. */
 	init_cpu_ops();

make_helpers/armv7-a-cpus.mk

@@ -39,8 +39,12 @@ endif
 #
 # ARMV7_SUPPORTS_VIRTUALIZATION
 # Defined if ARMv7 core supports the Virtualization extension.
+#
+# ARMV7_SUPPORTS_GENERIC_TIMER
+# Defined if ARMv7 core supports the Generic Timer extension.
 
 ifeq ($(filter yes,$(ARM_CORTEX_A7) $(ARM_CORTEX_A12) $(ARM_CORTEX_A15) $(ARM_CORTEX_A17)),yes)
 $(eval $(call add_define,ARMV7_SUPPORTS_LARGE_PAGE_ADDRESSING))
 $(eval $(call add_define,ARMV7_SUPPORTS_VIRTUALIZATION))
+$(eval $(call add_define,ARMV7_SUPPORTS_GENERIC_TIMER))
 endif