acc.c: Don't use C99 constructs, this breaks builds on Debian 8

[  160s] acc.c: In function 'get_highest_allowed_acc':
[  160s] acc.c:117:2: error: 'for' loop initial declarations are only allowed in C99 or C11 mode
[  160s]   for (int i = 9; i >= 0; i--) {
[  160s]   ^
[  160s] acc.c:117:2: note: use option -std=c99, -std=gnu99, -std=c11 or -std=gnu11 to compile your code
[  160s] acc.c: In function 'get_lowest_allowed_acc':
[  160s] acc.c:127:2: error: 'for' loop initial declarations are only allowed in C99 or C11 mode
[  160s]   for (int i = 0; i < 10; i++) {
[  160s]   ^
[  160s] Makefile:617: recipe for target 'acc.o' failed

Change-Id: I03722854634b2d6d6f1abac7c7553762b5fc6890
diff --git a/src/osmo-bsc/acc.c b/src/osmo-bsc/acc.c
index b25f2fd..72b4591 100644
--- a/src/osmo-bsc/acc.c
+++ b/src/osmo-bsc/acc.c
@@ -114,7 +114,9 @@
 
 static uint8_t get_highest_allowed_acc(uint16_t mask)
 {
-	for (int i = 9; i >= 0; i--) {
+	int i;
+
+	for (i = 9; i >= 0; i--) {
 		if (mask & (1 << i))
 			return i;
 	}
@@ -124,7 +126,9 @@
 
 static uint8_t get_lowest_allowed_acc(uint16_t mask)
 {
-	for (int i = 0; i < 10; i++) {
+	int i;
+
+	for (i = 0; i < 10; i++) {
 		if (mask & (1 << i))
 			return i;
 	}