Nuvoton: Add I2C & Serial Pin Name

[cyliangtw]

This PR is to add I2C & Serial pin name definition for compatibility in existing mbed samples.
It updates the following Nuvoton targets and passed Greentea test:

• NUMAKER_PFM_NUC472
• NUMAKER_PFM_M453
• NUMAKER_PFM_M487
• NUMAKER_PFM_NANO130

[0xc0170]

/morph build

[mbed-ci]

Build : FAILURE

Build number : 1273
Build artifacts/logs : http://mbed-os.s3-website-eu-west-1.amazonaws.com/?prefix=builds/6227/

[0xc0170]

Restarting

/morph build

[mbed-ci]

Build : FAILURE

Build number : 1276
Build artifacts/logs : http://mbed-os.s3-website-eu-west-1.amazonaws.com/?prefix=builds/6227/

[0xc0170]

/morph build

[mbed-ci]

Build : FAILURE

Build number : 1282
Build artifacts/logs : http://mbed-os.s3-website-eu-west-1.amazonaws.com/?prefix=builds/6227/

[cmonr]

ARM license issue. Trying again.
/morph build

[mbed-ci]

Build : SUCCESS

Build number : 1290
Build artifacts/logs : http://mbed-os.s3-website-eu-west-1.amazonaws.com/?prefix=builds/6227/

Triggering tests

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

[mbed-ci]

Exporter Build : SUCCESS

Build number : 952
Build artifacts/logs : http://mbed-os.s3-website-eu-west-1.amazonaws.com/?prefix=builds/exporter/6227/

[mbed-ci]

Test : SUCCESS

Build number : 1077
Test logs :http://mbed-os-logs.s3-website-us-west-1.amazonaws.com/?prefix=logs/6227/1077