e1000e: Replace PREEMPT_RT_FULL with PREEMPT_RT

Commit a555b1a added a delay after long writes on PREEMPT_RT-enabled
kernels, but using the PREEMPT_RT_FULL option, which has since been
replaced by just PREEMPT_RT.
Therefore, update the delay condition to check on PREEMPT_RT instead.

Signed-off-by: Shruthi Ravichandran <shruthi.ravichandran@ni.com>

drivers/net/ethernet/intel/Kconfig

@@ -87,7 +87,7 @@ config E1000E_HWTS
 config E1000_DELAY
 	bool "Add delays to e1000x drivers"
 	default n
-	depends on (E1000E || E1000) && PREEMPT_RT_FULL
+	depends on (E1000E || E1000) && PREEMPT_RT
 	help
 	  Enable delays after large numbers of MMIO writes to registers.
 	  The delays aid in preventing noticeable impact on real-time