arm64: cpufeature: remove duplicate ID_AA64ISAR2_EL1 entry

The ID register table should have one entry per ID register but
currently has two entries for ID_AA64ISAR2_EL1. Only one entry has an
override, and get_arm64_ftr_reg() can end up choosing the other, causing
the override to be ignored. Fix this by removing the duplicate entry.

While here, also make the check in sort_ftr_regs() more strict so that
duplicate entries can't be added in the future.

Fixes: def8c22 ("arm64: Add support of PAuth QARMA3 architected algorithm")
Signed-off-by: Kristina Martsenko <kristina.martsenko@arm.com>
Reviewed-by: Vladimir Murzin <vladimir.murzin@arm.com>
Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Link: https://lore.kernel.org/r/20220511162030.1403386-1-kristina.martsenko@arm.com
Signed-off-by: Will Deacon <will@kernel.org>

arch/arm64/kernel/cpufeature.c

@@ -654,7 +654,6 @@ static const struct __ftr_reg_entry {
 	ARM64_FTR_REG(SYS_ID_AA64ISAR0_EL1, ftr_id_aa64isar0),
 	ARM64_FTR_REG_OVERRIDE(SYS_ID_AA64ISAR1_EL1, ftr_id_aa64isar1,
 			       &id_aa64isar1_override),
-	ARM64_FTR_REG(SYS_ID_AA64ISAR2_EL1, ftr_id_aa64isar2),
 	ARM64_FTR_REG_OVERRIDE(SYS_ID_AA64ISAR2_EL1, ftr_id_aa64isar2,
 			       &id_aa64isar2_override),
 
@@ -810,7 +809,7 @@ static void __init sort_ftr_regs(void)
 		 * to sys_id for subsequent binary search in get_arm64_ftr_reg()
 		 * to work correctly.
 		 */
-		BUG_ON(arm64_ftr_regs[i].sys_id < arm64_ftr_regs[i - 1].sys_id);
+		BUG_ON(arm64_ftr_regs[i].sys_id <= arm64_ftr_regs[i - 1].sys_id);
 	}
 }