selftests/resctrl: Fix incorrect parsing of option "-t"

Resctrl test suite accepts command line argument "-t" to specify the
unit tests to run in the test list (e.g., -t mbm,mba,cmt,cat) as
documented in the help.

When calling strtok() to parse the option, the incorrect delimiters
argument ":\t" is used. As a result, passing "-t mbm,mba,cmt,cat" throws
an invalid option error.

Fix this by using delimiters argument "," instead of ":\t" for parsing
of unit tests list. At the same time, remove the unnecessary "spaces"
between the unit tests in help documentation to prevent confusion.

Fixes: 790bf585b0ee ("selftests/resctrl: Add Cache Allocation Technology (CAT) selftest")
Fixes: 78941183d1b1 ("selftests/resctrl: Add Cache QoS Monitoring (CQM) selftest")
Fixes: ecdbb911f22d ("selftests/resctrl: Add MBM test")
Fixes: 034c7678dd2c ("selftests/resctrl: Add README for resctrl tests")
Cc: [e-mail]
Signed-off-by: Xiaochen Shen <[e-mail]>
Reviewed-by: Tony Luck <[e-mail]>
Signed-off-by: Shuah Khan <[e-mail]>

tools/testing/selftests/resctrl/README

···
 
 usage: resctrl_tests [-h] [-b "benchmark_cmd [options]"] [-t test list] [-n no_of_bits]
         -b benchmark_cmd [options]: run specified benchmark for MBM, MBA and CMT default benchmark is builtin fill_buf
-        -t test list: run tests specified in the test list, e.g. -t mbm, mba, cmt, cat
+        -t test list: run tests specified in the test list, e.g. -t mbm,mba,cmt,cat
         -n no_of_bits: run cache tests using specified no of bits in cache bit mask
         -p cpu_no: specify CPU number to run the test. 1 is default
         -h: help

tools/testing/selftests/resctrl/resctrl_tests.c

···
 	printf("\t-b benchmark_cmd [options]: run specified benchmark for MBM, MBA and CMT\n");
 	printf("\t   default benchmark is builtin fill_buf\n");
 	printf("\t-t test list: run tests specified in the test list, ");
-	printf("e.g. -t mbm, mba, cmt, cat\n");
+	printf("e.g. -t mbm,mba,cmt,cat\n");
 	printf("\t-n no_of_bits: run cache tests using specified no of bits in cache bit mask\n");
 	printf("\t-p cpu_no: specify CPU number to run the test. 1 is default\n");
 	printf("\t-h: help\n");
···
 
 					return -1;
 				}
-				token = strtok(NULL, ":\t");
+				token = strtok(NULL, ",");
 			}
 			break;
 		case 'p':