Add IAR exporter for STM32L475VG (mcu of DISCO_L475VG_IOT01A)

[adustm]

Description

The mbed export -i IAR -m DISCO_L475VG_IOT01A command is failing.
With this PR, it is supported.

Status

READY

Migrations

NO

Steps to test or reproduce

before:
mbed export -i IAR -m DISCO_L475VG_IOT01A gives

project.py: error: DISCO_L475VG_IOT01A not supported by iar
[mbed] ERROR: "c:\python27\python.exe" returned error code 2.

after:
it works

[0xc0170]

/morph build

[mbed-ci]

Build : SUCCESS

Build number : 706
Build artifacts/logs : http://mbed-os.s3-website-eu-west-1.amazonaws.com/?prefix=builds/5707/

Triggering tests

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

[mbed-ci]

Exporter Build : FAILURE

Build number : 355
Build artifacts/logs : http://mbed-os.s3-website-eu-west-1.amazonaws.com/?prefix=builds/exporter/5707/

[mbed-ci]

Test : FAILURE

Build number : 539
Test logs :http://mbed-os-logs.s3-website-us-west-1.amazonaws.com/?prefix=logs/5707/539

[0xc0170]

/morph export-build

[mbed-ci]

Exporter Build : FAILURE

Build number : 363
Build artifacts/logs : http://mbed-os.s3-website-eu-west-1.amazonaws.com/?prefix=builds/exporter/5707/

[0xc0170]

/morph export-build

[mbed-ci]

Exporter Build : SUCCESS

Build number : 365
Build artifacts/logs : http://mbed-os.s3-website-eu-west-1.amazonaws.com/?prefix=builds/exporter/5707/

[0xc0170]

/morph test

[mbed-ci]

Test : SUCCESS

Build number : 545
Test logs :http://mbed-os-logs.s3-website-us-west-1.amazonaws.com/?prefix=logs/5707/545