net: fix sparse warnings in SNMP_UPD_PO_STATS(_BH)

ptr used to be a non __percpu pointer (result of a this_cpu_ptr
assignment, 7d720c3e4f0c4 ("percpu: add __percpu sparse annotations to
net")). Since d25398df59b56 ("net: avoid reloads in SNMP_UPD_PO_STATS"),
that's no longer the case, SNMP_UPD_PO_STATS uses this_cpu_add and ptr
is now __percpu.

Silence sparse warnings by preserving the original type and
annotation, and remove the out-of-date comment.

warning: incorrect type in initializer (different address spaces)
   expected unsigned long long *ptr
   got unsigned long long [noderef] <asn:3>*<noident>
warning: incorrect type in initializer (different address spaces)
   expected void const [noderef] <asn:3>*__vpp_verify
   got unsigned long long *<noident>
warning: incorrect type in initializer (different address spaces)
   expected void const [noderef] <asn:3>*__vpp_verify
   got unsigned long long *<noident>

Signed-off-by: Sabrina Dubroca <sd@queasysnail.net>
Acked-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/net/snmp.h

@@ -146,19 +146,15 @@ struct linux_xfrm_mib {
 
 #define SNMP_ADD_STATS(mib, field, addend)	\
 			this_cpu_add(mib->mibs[field], addend)
-/*
- * Use "__typeof__(*mib) *ptr" instead of "__typeof__(mib) ptr"
- * to make @ptr a non-percpu pointer.
- */
 #define SNMP_UPD_PO_STATS(mib, basefield, addend)	\
 	do { \
-		__typeof__(*mib->mibs) *ptr = mib->mibs;	\
+		__typeof__((mib->mibs) + 0) ptr = mib->mibs;	\
 		this_cpu_inc(ptr[basefield##PKTS]);		\
 		this_cpu_add(ptr[basefield##OCTETS], addend);	\
 	} while (0)
 #define SNMP_UPD_PO_STATS_BH(mib, basefield, addend)	\
 	do { \
-		__typeof__(*mib->mibs) *ptr = mib->mibs;	\
+		__typeof__((mib->mibs) + 0) ptr = mib->mibs;	\
 		__this_cpu_inc(ptr[basefield##PKTS]);		\
 		__this_cpu_add(ptr[basefield##OCTETS], addend);	\
 	} while (0)