[nrf fromlist] net: ip: Add a name to existing Kconfig choice

Update kconfig choice name to enable overriding
from other parts of the code.

Upstream PR: zephyrproject-rtos/zephyr#78852

Signed-off-by: Triveni Danda <[email protected]>

Author: D-Triveni

subsys/net/ip/Kconfig

@@ -663,7 +663,7 @@ config NET_BUF_TX_COUNT
 	  Each data buffer will occupy CONFIG_NET_BUF_DATA_SIZE + smallish
 	  header (sizeof(struct net_buf)) amount of data.
 
-choice
+choice NET_PKT_DATA_ALLOC_TYPE
 	prompt "Network packet data allocator type"
 	default NET_BUF_FIXED_DATA_SIZE
 	help