arc: eznps: fix allmodconfig kconfig warning

Fix kconfig warning for arch/arc/plat-eznps/Kconfig allmodconfig:

WARNING: unmet direct dependencies detected for CLKSRC_NPS
  Depends on [n]: GENERIC_CLOCKEVENTS [=y] && !PHYS_ADDR_T_64BIT [=y]
  Selected by [y]:
  - ARC_PLAT_EZNPS [=y]

Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Cc: Vineet Gupta <vgupta@synopsys.com>
Cc: Ofer Levi <oferle@mellanox.com>
Cc: linux-snps-arc@lists.infradead.org
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>