CONFIG_AMD_MEM_ENCRYPT is not available for thedefaultarchitecture x86.
Result is shown for architecture 64BIT

AMD Secure Memory Encryption (SME) support

modulename: mem_encrypt.ko

and/or

mem_encrypt_identity.ko

and/or

mem_encrypt_boot.ko

and/or

sev-es.ko

configname: CONFIG_AMD_MEM_ENCRYPT

Linux Kernel Configuration
└─>Processor type and features
└─>AMD Secure Memory Encryption (SME) support
In linux kernel since version 3.10 (release Date: 2013-06-30)  
Say yes to enable support for the encryption of system memory.
This requires an AMD processor that supports Secure Memory
Encryption (SME).