ONG amount precision and symbol on device display incorrect

[nickfujita]

When signing a transaction on the device, the asset symbol and amount shown for the transaction details for ONG is incorrect.

Steps to reproduce:

• Send a serialized transfer transaction
  • Test amount 0.05 ONG
• Navigate to view the transaction details on the device

Expected:

• Display should show ONG 0.05

Actual:

• Display shows ONT 50000000

[xizho10]

ONG Amount precision have fix in pull

[nickfujita]

PR: https://github.com/LedgerHQ/ledger-app-ont/pull/5