Update Linux to v5.4.2

Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/drivers/net/slip/slhc.c b/drivers/net/slip/slhc.c
index f4e93f5..58a69f8 100644
--- a/drivers/net/slip/slhc.c
+++ b/drivers/net/slip/slhc.c
@@ -91,8 +91,8 @@
 struct slcompress *
 slhc_init(int rslots, int tslots)
 {
-	register short i;
-	register struct cstate *ts;
+	short i;
+	struct cstate *ts;
 	struct slcompress *comp;
 
 	if (rslots < 0 || rslots > 255 || tslots < 0 || tslots > 255)
@@ -153,7 +153,7 @@
 void
 slhc_free(struct slcompress *comp)
 {
-	if ( comp == NULLSLCOMPR )
+	if ( IS_ERR_OR_NULL(comp) )
 		return;
 
 	if ( comp->tstate != NULLSLSTATE )
@@ -206,7 +206,7 @@
 static long
 decode(unsigned char **cpp)
 {
-	register int x;
+	int x;
 
 	x = *(*cpp)++;
 	if(x == 0){
@@ -227,14 +227,14 @@
 slhc_compress(struct slcompress *comp, unsigned char *icp, int isize,
 	unsigned char *ocp, unsigned char **cpp, int compress_cid)
 {
-	register struct cstate *ocs = &(comp->tstate[comp->xmit_oldest]);
-	register struct cstate *lcs = ocs;
-	register struct cstate *cs = lcs->next;
-	register unsigned long deltaS, deltaA;
-	register short changes = 0;
+	struct cstate *ocs = &(comp->tstate[comp->xmit_oldest]);
+	struct cstate *lcs = ocs;
+	struct cstate *cs = lcs->next;
+	unsigned long deltaS, deltaA;
+	short changes = 0;
 	int hlen;
 	unsigned char new_seq[16];
-	register unsigned char *cp = new_seq;
+	unsigned char *cp = new_seq;
 	struct iphdr *ip;
 	struct tcphdr *th, *oth;
 	__sum16 csum;
@@ -486,11 +486,11 @@
 int
 slhc_uncompress(struct slcompress *comp, unsigned char *icp, int isize)
 {
-	register int changes;
+	int changes;
 	long x;
-	register struct tcphdr *thp;
-	register struct iphdr *ip;
-	register struct cstate *cs;
+	struct tcphdr *thp;
+	struct iphdr *ip;
+	struct cstate *cs;
 	int len, hdrlen;
 	unsigned char *cp = icp;
 
@@ -543,7 +543,7 @@
 	switch(changes & SPECIALS_MASK){
 	case SPECIAL_I:		/* Echoed terminal traffic */
 		{
-		register short i;
+		short i;
 		i = ntohs(ip->tot_len) - hdrlen;
 		thp->ack_seq = htonl( ntohl(thp->ack_seq) + i);
 		thp->seq = htonl( ntohl(thp->seq) + i);
@@ -637,7 +637,7 @@
 int
 slhc_remember(struct slcompress *comp, unsigned char *icp, int isize)
 {
-	register struct cstate *cs;
+	struct cstate *cs;
 	unsigned ihl;
 
 	unsigned char index;