coding guidelines: comply with MISRA Rule 13.4

- avoid to use assignment expression value

Signed-off-by: Hess Nathan <nhess@baumer.com>

lib/os/cbprintf_complete.c

diff --git a/lib/os/cbprintf_complete.c b/lib/os/cbprintf_complete.c
index 08779d1..fe95fab 100644
--- a/lib/os/cbprintf_complete.c
+++ b/lib/os/cbprintf_complete.c
@@ -1060,7 +1060,7 @@
 			/* Fraction is subnormal.  Normalize it and correct
 			 * the exponent.
 			 */
-			while (((fract <<= 1) & BIT_63) == 0) {
+			for (fract <<= 1; (fract & BIT_63) == 0; fract <<= 1) {
 				expo--;
 			}
 		}

lib/utils/rb.c

diff --git a/lib/utils/rb.c b/lib/utils/rb.c
index dc4bc06..5457224 100644
--- a/lib/utils/rb.c
+++ b/lib/utils/rb.c
@@ -537,7 +537,7 @@
 	f->stack[f->top] = n;
 	f->is_left[f->top] = 0U;
 
-	while ((n = get_child(n, 0U)) != NULL) {
+	for (n = get_child(n, 0U); n != NULL; n = get_child(n, 0U)) {
 		f->top++;
 		f->stack[f->top] = n;
 		f->is_left[f->top] = 1;