arm64: cpufeature: Define helpers for sys_reg id

Define helper macros to extract op0, op1, CRn, CRm & op2
for a given sys_reg id. While at it remove the explicit
masking only used for Op0.

Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>

arch/arm64/include/asm/sysreg.h

@@ -32,8 +32,27 @@
  *	[11-8]  : CRm
  *	[7-5]   : Op2
  */
+#define Op0_shift	19
+#define Op0_mask	0x3
+#define Op1_shift	16
+#define Op1_mask	0x7
+#define CRn_shift	12
+#define CRn_mask	0xf
+#define CRm_shift	8
+#define CRm_mask	0xf
+#define Op2_shift	5
+#define Op2_mask	0x7
+
 #define sys_reg(op0, op1, crn, crm, op2) \
-	((((op0)&3)<<19)|((op1)<<16)|((crn)<<12)|((crm)<<8)|((op2)<<5))
+	(((op0) << Op0_shift) | ((op1) << Op1_shift) | \
+	 ((crn) << CRn_shift) | ((crm) << CRm_shift) | \
+	 ((op2) << Op2_shift))
+
+#define sys_reg_Op0(id)	(((id) >> Op0_shift) & Op0_mask)
+#define sys_reg_Op1(id)	(((id) >> Op1_shift) & Op1_mask)
+#define sys_reg_CRn(id)	(((id) >> CRn_shift) & CRn_mask)
+#define sys_reg_CRm(id)	(((id) >> CRm_shift) & CRm_mask)
+#define sys_reg_Op2(id)	(((id) >> Op2_shift) & Op2_mask)
 
 #ifndef CONFIG_BROKEN_GAS_INST