Silence signed/unsigned comparison warnings in GCC.

i2c_frequency() compares a uint32_t ref variable to the int hz
function parameter passed in by the caller.  I forced this to be an
uint32_t comparison.

i2c_slave_write() declared i and count variables to be of type uint32_t
but used them as int type throughout the code (in comparisons and
returns) so I switched them to be of signed int type.

spi_frequency() contains a change similar to that made in
i2c_frequency().

Author: adamgreen

libraries/mbed/targets/hal/TARGET_Freescale/TARGET_KL25Z/i2c_api.c

@@ -215,7 +215,7 @@ void i2c_frequency(i2c_t *obj, int hz) {
     for (i = 1; i < 5; i*=2) {
         for (j = 0; j < 0x40; j++) {
             ref = PCLK / (i*ICR[j]);
-            if (ref > hz)
+            if (ref > (uint32_t)hz)
                 continue;
             error = hz - ref;
             if (error < p_error) {
@@ -392,7 +392,7 @@ int i2c_slave_read(i2c_t *obj, char *data, int length) {
 }
 
 int i2c_slave_write(i2c_t *obj, const char *data, int length) {
-    uint32_t i, count = 0;
+    int i, count = 0;
 
     // set tx mode
     obj->i2c->C1 |= I2C_C1_TX_MASK;

libraries/mbed/targets/hal/TARGET_Freescale/TARGET_KL25Z/spi_api.c

@@ -153,7 +153,7 @@ void spi_frequency(spi_t *obj, int hz) {
         divisor = 2;
         for (spr = 0; spr <= 8; spr++, divisor *= 2) {
             ref = PCLK / (prescaler*divisor);
-            if (ref > hz)
+            if (ref > (uint32_t)hz)
                 continue;
             error = hz - ref;
             if (error < p_error) {