treewide: Move skip_atoi function to commonlib

BUG=none
TEST=Build and verify on Screebo
TEST=make unit-tests

```
$ make tests/commonlib/bsd/string-test
[==========] tests_commonlib_bsd_string-test(tests): Running 1 test(s).
[ RUN      ] test_skip_atoi
[       OK ] test_skip_atoi
[==========] tests_commonlib_bsd_string-test(tests): 1 test(s) run.
[  PASSED  ] 1 test(s).
```

Change-Id: Ifaaa80d0c696a625592ce301f9e3eefb2b4dcd98
Signed-off-by: Maximilian Brune <maximilian.brune@9elements.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/82910
Reviewed-by: Jakub Czapiga <czapiga@google.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Subrata Banik <subratabanik@google.com>

src/commonlib/Makefile.mk

@@ -65,3 +65,7 @@ decompressor-y += bsd/gcd.c
 all-y += bsd/gcd.c
 
 all-y += bsd/ipchksum.c
+
+decompressor-y += bsd/string.c
+smm-y += bsd/string.c
+all-y += bsd/string.c

src/commonlib/bsd/include/commonlib/bsd/string.h

@@ -0,0 +1,10 @@
+/* SPDX-License-Identifier: BSD-3-Clause */
+
+#ifndef _COMMONLIB_BSD_STRING_H_
+#define _COMMONLIB_BSD_STRING_H_
+
+#include <stdint.h>
+
+unsigned int skip_atoi(char **ptr);
+
+#endif  /* _COMMONLIB_BSD_STRING_H_ */

src/commonlib/bsd/string.c

@@ -0,0 +1,15 @@
+/* SPDX-License-Identifier: BSD-3-Clause */
+
+#include <commonlib/bsd/string.h>
+#include <ctype.h>
+
+unsigned int skip_atoi(char **ptr)
+{
+	unsigned int result = 0;
+	char *str;
+
+	for (str = *ptr; isdigit(str[0]); str++)
+		result = result * 10 + (str[0] - '0');
+	*ptr = str;
+	return result;
+}

src/include/string.h

@@ -3,6 +3,7 @@
 #ifndef STRING_H
 #define STRING_H
 
+#include <commonlib/bsd/string.h>
 #include <stddef.h>
 
 void *memcpy(void *dest, const void *src, size_t n);
@@ -36,11 +37,4 @@ long atol(const char *str);
  */
 char *strrchr(const char *s, int c);
 
-/*
- * Parses an unsigned integer and moves the input pointer forward to the first
- * character that's not a valid digit. s and *s must not be NULL. Result
- * undefined if it overruns the return type size.
- */
-unsigned int skip_atoi(char **s);
-
 #endif /* STRING_H */

src/lib/string.c

@@ -125,15 +125,6 @@ int strncmp(const char *s1, const char *s2, int maxlen)
 	return 0;
 }
 
-unsigned int skip_atoi(char **s)
-{
-	unsigned int i = 0;
-
-	while (isdigit(**s))
-		i = i*10 + *((*s)++) - '0';
-	return i;
-}
-
 int strspn(const char *str, const char *spn)
 {
 	int ret = 0;