soc: espressif: Fix psram0 node size and smh heap size calculation

Fixing multiple things related to psram usage:
- fix conflicting psram0 dts node for all ESP32 SiP and SoC.
- fix dcache and icache area used in psram mapping.
- fix smh spiram heap allocations.
- add `espressif,esp32-psram` compatible to set psram0 size in dts.

Signed-off-by: Marek Matej <marek.matej@espressif.com>