TARGET_STM: masking logic for CAN rx interrupt is wrong

[pavels]

Description of defect

Target(s) affected by this defect ?

STM

Toolchain(s) (name and version) displaying this defect ?

n/a

What version of Mbed-os are you using (tag or sha) ?

mbed-os-6.17.0

What version(s) of tools are you using. List all that apply (E.g. mbed-cli)

n/a

How is this defect reproduced ?

When there are multiple interrupts registered for CAN device, rx interrupt will not fire if other interrupt happens sooner.

There is a logic to mask rx interrupt, because it can't be cleared in other way than by read from the CAN interface, byt that should be differed to thread out from interrupt.

The problem is, that the current implementation is flawed in a way, that it not only masks rx interrupt after it happens, but it also masks it after any interrupt happens effectively making it unusable.

[mbedmain]

@pavels thank you for raising this issue.Please take a look at the following comments:

Could you add some more detail to the description? A good description should be at least 25 words.
What toolchain(s) are you using?
It would help if you could also specify the versions of any tools you are using?

NOTE: If there are fields which are not applicable then please just add 'n/a' or 'None'. This indicates to us that at least all the fields have been considered.
Please update the issue header with the missing information.

[pavels]

And here is PR to fix the issue #15461