Update to Mbed OS 5.15.5

[teetak01]

https://github.com/ARMmbed/mbed-os/releases/tag/mbed-os-5.15.5

[teetak01]

run-ci

[iot-pdmc]

Test run: FAILED

---

Test summary:
Executed: 24
Failed: 0
Skipped: 0
Errors: 0

Failed to build following targets:
NUMAKER_PFM_NUC472-GCC_ARM-TCP
Build artifacts

posted-by-tag: https://jenkins-client.isgtesting.com/job/mbed-os-example-pelion/

[teetak01]

@MarceloSalazar any idea why NUMAKER_PFM_NUC472-GCC_ARM-TCP no longer fits on target with 5.15.5?

/usr/local/gcc-arm-none-eabi-9-2019-q4-major/bin/../lib/gcc/arm-none-eabi/9.2.1/../../../../arm-none-eabi/bin/ld: region RAM_INTERN' overflowed by 800 bytes`

[MarceloSalazar]

Sorry I don't know.
@ARMmbed/team-nuvoton can you please have a look and comment?

[ccli8]

@teetak01 NUMAKER_PFM_NUC472 has 64KiB internal RAM and 1MiB external RAM. The internal RAM has overflowed. I will adjust memory layout to fit this program.

[cyliangtw]

We will cross check the root cause in MBEDTLS_ENTROPY type, OS v5.15.5 or other manners.
Then, come out the better solution to resolve this RAM overflow issue.

[cyliangtw]

@teetak01, @MarceloSalazar
NUMAKER_PFM_NUC472-GCC_ARM build fail issue could be resolved by fixing NUC472 SD buffer alignment issue in mbed-os PR #13512