samples: boards: nxp: mimxrt1060_evk: Remove default selected options

Remove Kconfig symbols that are default selected based on the device tree.

Signed-off-by: Pieter De Gendt <[email protected]>

Author: pdgendt

samples/boards/nxp/mimxrt1060_evk/system_off/prj.conf

@@ -2,7 +2,4 @@ CONFIG_PM=y
 
 # Enable the SNVS RTC
 CONFIG_COUNTER=y
-CONFIG_COUNTER_MCUX_SNVS=y
-CONFIG_COUNTER_MCUX_SNVS_SRTC=y
-CONFIG_COUNTER_MCUX_SNVS_SRTC_WAKE=y
 CONFIG_GPIO=y