Wrong maximum number of LMKs in docs (IDFGH-11890)

[rguca]

The docs state the maximum number of LMKs is 6:

esp-idf/docs/en/api-reference/network/esp_now.rst

Line 56 in b3f7e2c

* LMK of the paired device is used to encrypt the vendor-specific action frame with the CCMP method. The maximum number of different LMKs is six. If the LMK of the paired device is not set, the vendor-specific action frame will not be encrypted.

After some testing, this seems not to be true. The maximum number of LMKs is defined by CONFIG_ESP_WIFI_ESPNOW_MAX_ENCRYPT_NUM.

[zhangyanjiaoesp]

@rguca yes, you are right, we will update the doc. Thanks for your correction.