Fixes https://github.com/vroland/epdiy/issues/196

[martinberlin]

Fixes #196 avoiding to do:

rtc_gpio_isolate(GPIO_NUM_5);

in the V2 / Lilygo hardware that uses 5 as I2S Clock. On the other models that use number 15 this does not seem to trigger.

[jdoubleu]

I think these changes in 6e9d620 from the #180 PR are somewhat related to this one.

[martinberlin]

It can be related, but this one specifically triggers on IO5, when using:

rtc_gpio_isolate(GPIO_NUM_5);

This is not triggering on IO 15 that is used by V6. And I really don't know what is going on with that specific pin on Lilygo model. But still not sure if my fix is appropriate so maybe we wait till the #180 PR is merged before doing this.
In older versions of this component or even the LilyGO version this didn't happen since there was no i2s_gpio_detach() this was created afterwords (I think)

[lanistor]

rtc_gpio_isolate(GPIO_NUM_12) this makes our buzzer not sound, because the same pin is used, is this sentence necessary?