STM32F1 RTC : wrong Sunday value

[jeromecoutant]

Description

In struc tm, tm_wday is the day since Sunday with value from 0 to 6

In ST RTC driver, Sunday is coded as 7 for all STM32 family,
except for STM32F1, where value is 0

Pull request type

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

[cmonr]

/morph build

[mbed-ci]

Build : SUCCESS

Build number : 2786
Build artifacts/logs : http://mbed-os.s3-website-eu-west-1.amazonaws.com/?prefix=builds/7777/

Triggering tests

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

[mbed-ci]

Exporter Build : SUCCESS

Build number : 2417
Build artifacts/logs : http://mbed-os.s3-website-eu-west-1.amazonaws.com/?prefix=builds/exporter/7777/

[cmonr]

/morph test

[mbed-ci]

Test : SUCCESS

Build number : 2542
Test logs :http://mbed-os-logs.s3-website-us-west-1.amazonaws.com/?prefix=logs/7777/2542