sched_stress: Use time_t instead of long for type

This fixes warnings on musl:

| sched_driver.c:744:43: error: passing argument 1 of 'ctime' from incompatible pointer type [-Wincompatible-pointer-types]
|   744 |         printf("\nend time = %s\n", ctime(&end_time));
|       |                                           ^~~~~~~~~

Link: https://lore.kernel.org/ltp/[email protected]/
Reviewed-by: Petr Vorel <[email protected]>
Signed-off-by: Khem Raj <[email protected]>

Author: kraj

testcases/kernel/sched/sched_stress/sched_driver.c

@@ -136,7 +136,7 @@ int debug = 0;
 /*
  * Function prototypes
  */
-void startup(long);
+void startup(time_t);
 int start_testcase(char *, char *, char *, char *, char *, char *);
 int process_slots_in_use();
 int available_user_process_slots();
@@ -251,7 +251,7 @@ int main(int argc, char **argv)
  * information to the screen and .  It also initializes the	 *
  * process id list and other global variables.	 			 *
  *-----------------------------------------------------------------------*/
-void startup(long start_time)
+void startup(time_t start_time)
 {
 	char tempbuffer[50];	/* temporary buffer to hold names */
 
@@ -734,7 +734,7 @@ void kill_short_term_testcases()
 void finishup(start_time)
 long start_time;		/* starting time to calculate elapsed time */
 {
-	long end_time;		/* time when program finished */
+	time_t end_time;		/* time when program finished */
 
 	/*
 	 * Get the end time and calculate elapsed time; write all this out