nimble/ll: Fix BLE_LL_CONN_INIT_MIN_WIN_OFFSET
nimble/ll: Fix BLE_LL_CONN_INIT_MIN_WIN_OFFSET

The code which calculates earliest connection event start does not take
BLE_LL_CONN_INIT_MIN_WIN_OFFSET into account, but we still update tx
windows offset in state machine with its value. As a result when this
setting is set to non-zero value we schedule first connection event
earlier than what slave calculates from CONNECT_IND PDU so connection
cannot be established.

andrzej-kaczmarek/apache-mynewt-core,mlaz/mynewt-core,andrzej-kaczmarek/incubator-mynewt-core,mlaz/mynewt-core,andrzej-kaczmarek/incubator-mynewt-core,andrzej-kaczmarek/apache-mynewt-core,mlaz/mynewt-core,andrzej-kaczmarek/incubator-mynewt-core,andrzej-kaczmarek/apache-mynewt-core,andrzej-kaczmarek/incubator-mynewt-core,mlaz/mynewt-core,andrzej-kaczmarek/incubator-mynewt-core,mlaz/mynewt-core,andrzej-kaczmarek/apache-mynewt-core