bluetooth: rpc: Remove dependency on BT_DRIVERS

This dependency introduced as a fix for cmake warnings doesn't
seem to be needed anymore but it leads to a dependency loop with
BT_CTLR_ADV_EXT_SUPPORT.
This commit basically reverts 43c4519.

Signed-off-by: Andrzej Głąbek <[email protected]>

Author: anangl

subsys/bluetooth/rpc/Kconfig

@@ -72,10 +72,6 @@ if BT_RPC_CLIENT
 config HEAP_MEM_POOL_SIZE
 	default 4096
 
-config BT_DRIVERS
-	bool "Bluetooth Drivers"
-	default n
-
 endif # BT_RPC_CLIENT
 
 if BT_RPC_HOST