tpm: return false from tpm_amd_is_rng_defective on non-x86 platforms

tpm_amd_is_rng_defective is for dealing with an issue related to the
AMD firmware TPM, so on non-x86 architectures just have it inline and
return false.

Cc: stable@vger.kernel.org # v6.3+
Reported-by: Sachin Sant <sachinp@linux.ibm.com>
Reported-by: Aneesh Kumar K. V <aneesh.kumar@linux.ibm.com>
Closes: https://lore.kernel.org/lkml/99B81401-DB46-49B9-B321-CF832B50CAC3@linux.ibm.com/
Fixes: f1324bb ("tpm: disable hwrng for fTPM on some AMD designs")
Signed-off-by: Jerry Snitselaar <jsnitsel@redhat.com>
Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org>
Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org>

Author: snits

drivers/char/tpm/tpm-chip.c

@@ -518,6 +518,7 @@ static int tpm_add_legacy_sysfs(struct tpm_chip *chip)
  * 6.x.y.z series: 6.0.18.6 +
  * 3.x.y.z series: 3.57.y.5 +
  */
+#ifdef CONFIG_X86
 static bool tpm_amd_is_rng_defective(struct tpm_chip *chip)
 {
 	u32 val1, val2;
@@ -566,6 +567,12 @@ static bool tpm_amd_is_rng_defective(struct tpm_chip *chip)
 
 	return true;
 }
+#else
+static inline bool tpm_amd_is_rng_defective(struct tpm_chip *chip)
+{
+	return false;
+}
+#endif /* CONFIG_X86 */
 
 static int tpm_hwrng_read(struct hwrng *rng, void *data, size_t max, bool wait)
 {