Cellular: WISE_1570's system clock back to HSE_XTAL

[mirelachirica]

Description

There was need to set LPUART clock to HSI for WISE_1570 (details in PR #7489). Initially this was not possible without setting the system clock to HSI, too. This problem has been fixed in PR: #7498. Now wise_1570's system clock can be set back to original type: HSE_XTAL.

Pull request type

[x] Fix
[ ] Refactor
[ ] Target update
[ ] Feature
[ ] Breaking change

[cmonr]

/morph build

[mbed-ci]

Build : SUCCESS

Build number : 2763
Build artifacts/logs : http://mbed-os.s3-website-eu-west-1.amazonaws.com/?prefix=builds/7731/

Triggering tests

/morph test
/morph uvisor-test
/morph export-build
/morph mbed2-build

[mbed-ci]

Exporter Build : SUCCESS

Build number : 2392
Build artifacts/logs : http://mbed-os.s3-website-eu-west-1.amazonaws.com/?prefix=builds/exporter/7731/

[mbed-ci]

Test : SUCCESS

Build number : 2489
Test logs :http://mbed-os-logs.s3-website-us-west-1.amazonaws.com/?prefix=logs/7731/2489