netfilter: nf_tables: constify nft_reg_load{8, 16, 64}()

This patch constifies the pointer to source register data that is passed
as an input parameter.

Signed-off-by: Pablo Neira Ayuso <[e-mail]>
Signed-off-by: David S. Miller <[e-mail]>

include/net/netfilter/nf_tables.h

···
 	*(u8 *)dreg = val;
 }
 
-static inline u8 nft_reg_load8(u32 *sreg)
+static inline u8 nft_reg_load8(const u32 *sreg)
 {
 	return *(u8 *)sreg;
 }
···
 	*(u16 *)dreg = val;
 }
 
-static inline u16 nft_reg_load16(u32 *sreg)
+static inline u16 nft_reg_load16(const u32 *sreg)
 {
 	return *(u16 *)sreg;
 }
···
 	put_unaligned(val, (u64 *)dreg);
 }
 
-static inline u64 nft_reg_load64(u32 *sreg)
+static inline u64 nft_reg_load64(const u32 *sreg)
 {
 	return get_unaligned((u64 *)sreg);
 }