tpm: Enable TCG_TPM2_HMAC by default only for X86_64

Given the not fully root caused performance issues on non-x86 platforms, enable the feature by default only for x86-64. That is the platform it brings the most value and has gone most of the QA. Can be reconsidered later and can be obviously opt-in enabled too on any arch.

---
 drivers/char/tpm/Kconfig | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

index e63a6a17793c..cf0be8a7939d 100644
@@ -29,7 +29,7 @@ if TCG_TPM
 
 config TCG_TPM2_HMAC
 	bool "Use HMAC and encrypted transactions on the TPM bus"
-	default y
+	default X86_64
 	select CRYPTO_ECDH
 	select CRYPTO_LIB_AESCFB
 	select CRYPTO_LIB_SHA256

2.45.1