mbedtls/external: support decoding multiple signer's cert

Support decoding multiple signer's cert in the signed data within
a PKCS7 message.

The PR for this patch is at:
https://github.com/Mbed-TLS/mbedtls/pull/9001

For enabling EFI loader PKCS7 features with MbedTLS build,
we need this patch on top of MbedTLS v3.6.0 before it is merged into
the next MbedTLS LTS release.

Signed-off-by: Raymond Mao <raymond.mao@linaro.org>
1 file changed