dts: bindings: wifi: Make 5G settings optional

For nRF7001 which is a 2.4GHz only device, these 5G related TX power
settings are unnecessary.

Signed-off-by: Chaitanya Tata <Chaitanya.Tata@nordicsemi.no>

Author: krish2718

dts/bindings/wifi/nordic,nrf700x-tx-power.yaml

@@ -23,25 +23,19 @@ properties:
     description: 8-bit values for max tx power in 2.4GHz band for MCS7
   max-pwr-5g-low-mcs0:
     type: int
-    required: true
     description: 8-bit values for max tx power in 5GHz band MCS0 low sub-band
   max-pwr-5g-low-mcs7:
     type: int
-    required: true
     description: 8-bit values for max tx power in 5GHz band MCS7 low sub-band
   max-pwr-5g-mid-mcs0:
     type: int
-    required: true
     description: 8-bit values for max tx power in 5GHz band MCS0 mid sub-band
   max-pwr-5g-mid-mcs7:
     type: int
-    required: true
     description: 8-bit values for max tx power in 5GHz band MCS7 mid sub-band
   max-pwr-5g-high-mcs0:
     type: int
-    required: true
     description: 8-bit values for max tx power in 5GHz band MCS0 high sub-band
   max-pwr-5g-high-mcs7:
     type: int
-    required: true
     description: 8-bit values for max tx power in 5GHz band MCS7 high sub-band