arm64/cpufeature: Drop TraceFilt feature exposure from ID_DFR0 register

ID_DFR0 based TraceFilt feature should not be exposed to guests. Hence lets
drop it.

Cc: Catalin Marinas <[email protected]>
Cc: Will Deacon <[email protected]>
Cc: Marc Zyngier <[email protected]>
Cc: Mark Rutland <[email protected]>
Cc: James Morse <[email protected]>
Cc: Suzuki K Poulose <[email protected]>
Cc: [email protected]
Cc: [email protected]

Suggested-by: Mark Rutland <[email protected]>
Signed-off-by: Anshuman Khandual <[email protected]>
Reviewed-by: Suzuki K Poulose <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Will Deacon <[email protected]>

Author: Anshuman Khandual

arch/arm64/kernel/cpufeature.c

@@ -440,7 +440,7 @@ static const struct arm64_ftr_bits ftr_id_pfr1[] = {
 };
 
 static const struct arm64_ftr_bits ftr_id_dfr0[] = {
-	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, 28, 4, 0),
+	/* [31:28] TraceFilt */
 	S_ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, 24, 4, 0xf),	/* PerfMon */
 	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, 20, 4, 0),
 	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, 16, 4, 0),