Replace space and tab checks with isblank

These are various places I found that checked for conditions equivalent
to isblank.

Signed-off-by: Jason Hobbs <jason.hobbs@calxeda.com>
diff --git a/common/command.c b/common/command.c
index ed931d7..2c0bf53 100644
--- a/common/command.c
+++ b/common/command.c
@@ -27,6 +27,7 @@
 
 #include <common.h>
 #include <command.h>
+#include <linux/ctype.h>
 
 /*
  * Use puts() instead of printf() to avoid printf buffer overflow
@@ -165,7 +166,7 @@
 	static char tmp_buf[512];
 	int space;
 
-	space = last_char == '\0' || last_char == ' ' || last_char == '\t';
+	space = last_char == '\0' || isblank(last_char);
 
 	if (space && argc == 1)
 		return env_complete("", maxv, cmdv, sizeof(tmp_buf), tmp_buf);
@@ -206,7 +207,7 @@
 	}
 
 	/* more than one arg or one but the start of the next */
-	if (argc > 1 || (last_char == '\0' || last_char == ' ' || last_char == '\t')) {
+	if (argc > 1 || (last_char == '\0' || isblank(last_char))) {
 		cmdtp = find_cmd(argv[0]);
 		if (cmdtp == NULL || cmdtp->complete == NULL) {
 			cmdv[0] = NULL;
@@ -257,7 +258,7 @@
 	while (argc < argvsz - 1) {
 
 		/* skip any white space */
-		while ((*s == ' ') || (*s == '\t'))
+		while (isblank(*s))
 			++s;
 
 		if (*s == '\0')	/* end of s, no more args	*/
@@ -266,7 +267,7 @@
 		argv[argc++] = s;	/* begin of argument string	*/
 
 		/* find end of string */
-		while (*s && (*s != ' ') && (*s != '\t'))
+		while (*s && !isblank(*s))
 			++s;
 
 		if (*s == '\0')		/* end of s, no more args	*/
diff --git a/common/main.c b/common/main.c
index d812aa1..7be2955 100644
--- a/common/main.c
+++ b/common/main.c
@@ -40,6 +40,7 @@
 #endif
 
 #include <post.h>
+#include <linux/ctype.h>
 
 #if defined(CONFIG_SILENT_CONSOLE) || defined(CONFIG_POST) || defined(CONFIG_CMDLINE_EDITING)
 DECLARE_GLOBAL_DATA_PTR;
@@ -1097,7 +1098,7 @@
 	while (nargs < CONFIG_SYS_MAXARGS) {
 
 		/* skip any white space */
-		while ((*line == ' ') || (*line == '\t'))
+		while (isblank(*line))
 			++line;
 
 		if (*line == '\0') {	/* end of line, no more args	*/
@@ -1111,7 +1112,7 @@
 		argv[nargs++] = line;	/* begin of argument string	*/
 
 		/* find end of string */
-		while (*line && (*line != ' ') && (*line != '\t'))
+		while (*line && !isblank(*line))
 			++line;
 
 		if (*line == '\0') {	/* end of line, no more args	*/