Update mbedtls to version 3.6.2

This new update to the LTS branch of MbedTLS provides
the fix for a buffer underrun vulnerability. TF-A does
not use the previously vulnerable functions
`mbedtls_pk_write_key_der` or `mbedtls_pk_write_key_pem`.
Full patch notes to this MbedTLS update can be found at
https://github.com/Mbed-TLS/mbedtls/releases/tag/mbedtls-3.6.2.

Signed-off-by: Ryan Everett <ryan.everett@arm.com>
Change-Id: I3496fbe54c3d85f7a5330b49cd77ccd16f7cb7fa
(cherry picked from commit f3eb26844acefd8e78e1b69e99eeecca9b21ac08)
3 files changed