cpupower: Fix NULL but dereferenced coccicheck errors

Fix NULL but dereferenced coccicheck errors found by:

make coccicheck MODE=report M=tools/power/cpupower

tools/power/cpupower/lib/cpufreq.c:384:19-23: ERROR: first is NULL but dereferenced.
tools/power/cpupower/lib/cpufreq.c:440:19-23: ERROR: first is NULL but dereferenced.
tools/power/cpupower/lib/cpufreq.c:308:19-23: ERROR: first is NULL but dereferenced.
tools/power/cpupower/lib/cpufreq.c:753:19-23: ERROR: first is NULL but dereferenced.

Signed-off-by: Shuah Khan <[e-mail]>

tools/power/cpupower/lib/cpufreq.c

···
 			} else {
 				first = malloc(sizeof(*first));
 				if (!first)
-					goto error_out;
+					return NULL;
 				current = first;
 			}
 			current->first = first;
···
 			} else {
 				first = malloc(sizeof(*first));
 				if (!first)
-					goto error_out;
+					return NULL;
 				current = first;
 			}
 			current->first = first;
···
 			} else {
 				first = malloc(sizeof(*first));
 				if (!first)
-					goto error_out;
+					return NULL;
 				current = first;
 			}
 			current->first = first;
···
 			} else {
 				first = malloc(sizeof(*first));
 				if (!first)
-					goto error_out;
+					return NULL;
 				current = first;
 			}
 			current->first = first;
···
 			} else {
 				first = malloc(sizeof(*first));
 				if (!first)
-					goto error_out;
+					return NULL;
 				current = first;
 			}
 			current->first = first;