main: Fix typos and checkpatch warnings in command line reading

There are a few over-long lines and other checkpatch problems in this area
of the code. Prepare the ground for the next patch by tidying these up.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Joe Hershberger <joe.hershberger@ni.com>

common/main.c

@@ -1082,14 +1082,14 @@ int readline_into_buffer(const char *const prompt, char *buffer, int timeout)
 		case '\n':
 			*p = '\0';
 			puts ("\r\n");
-			return (p - p_buf);
+			return p - p_buf;
 
 		case '\0':			/* nul			*/
 			continue;
 
 		case 0x03:			/* ^C - break		*/
 			p_buf[0] = '\0';	/* discard input */
-			return (-1);
+			return -1;
 
 		case 0x15:			/* ^U - erase line	*/
 			while (col > plen) {
@@ -1132,7 +1132,7 @@ int readline_into_buffer(const char *const prompt, char *buffer, int timeout)
 					char buf[2];
 
 					/*
-					 * Echo input using puts() to force am
+					 * Echo input using puts() to force an
 					 * LCD flush if we are using an LCD
 					 */
 					++col;