STM32: Fix disabling of IRQs shared by multiple events

[mattbrown015]

Description

Proposed fix for STM32: gpio_irq_disable Disables all InterruptIn Instances Sharing EXTI9_5 or EXTI15_10 #8021.

Discern if an IRQ is being shared by multiple events and only disable the IRQ if no events are using it.

There are a great many combinations and permutations of targets, IRQs and events. This change solves my problem but I've only tried it on a STM32L442KC and I've only enabled/disabled EXTI9_5.

Pull request type

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

[jeromecoutant]

Hi
ST CI tests started
Thx

[screamerbg]

@jeromecoutant Any update on this?
@0xc0170 what about Mbed CI tests?

[0xc0170]

@jeromecoutant assuming you approved after all tests passed for other platforms

[jeromecoutant]

Yes CI test shield all OK with all STM32 families

[0xc0170]

/morph build

[mbed-ci]

Build : SUCCESS

Build number : 3152
Build artifacts/logs : http://mbed-os.s3-website-eu-west-1.amazonaws.com/?prefix=builds/8037/

Triggering tests

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

[mbed-ci]

Exporter Build : SUCCESS

Build number : 2756
Build artifacts/logs : http://mbed-os.s3-website-eu-west-1.amazonaws.com/?prefix=builds/exporter/8037/

[mbed-ci]

Test : SUCCESS

Build number : 2957
Test logs :http://mbed-os-logs.s3-website-us-west-1.amazonaws.com/?prefix=logs/8037/2957

[0xc0170]

/morph mbed2-build