Fix minimum size description of challenge

The server-provided challenge is almost always smaller than 32 bytes,
so we cannot enforce that as a minimum. I fixed up the CDDL a while
back, but missed one mention of the 32 byte minimum in the description.

Test: n/a (it's a comment)
Bug: 272392463
Change-Id: Ia5994e2b7cf107ab131c6b028bee7881d0e657ac
diff --git a/security/rkp/aidl/android/hardware/security/keymint/IRemotelyProvisionedComponent.aidl b/security/rkp/aidl/android/hardware/security/keymint/IRemotelyProvisionedComponent.aidl
index 5bd2145..35b83dd 100644
--- a/security/rkp/aidl/android/hardware/security/keymint/IRemotelyProvisionedComponent.aidl
+++ b/security/rkp/aidl/android/hardware/security/keymint/IRemotelyProvisionedComponent.aidl
@@ -315,7 +315,7 @@
      *
      * @param in challenge contains a byte string from the provisioning server which will be
      *        included in the signed data of the CSR structure. Different provisioned backends may
-     *        use different semantic data for this field, but the supported sizes must be between 32
+     *        use different semantic data for this field, but the supported sizes must be between 16
      *        and 64 bytes, inclusive.
      *
      * @return the following CBOR Certificate Signing Request (Csr) serialized into a byte array: