feat(PeriphDrivers): Avoid div-by-zero in SPI SetFrequency calls (#1552)

Signed-off-by: Pete Johanson <pete.johanson@analog.com>

Author: petejohanson-adi

Libraries/PeriphDrivers/Source/SPI/spi_reva1.c

@@ -190,6 +190,10 @@ int MXC_SPI_RevA1_SetFrequency(mxc_spi_reva_regs_t *spi, unsigned int hz)
     int hi_clk, lo_clk, scale;
     uint32_t freq_div;
 
+    if (!hz) {
+        return E_BAD_PARAM;
+    }
+
     // Check if frequency is too high
     if (hz > PeripheralClock) {
         return E_BAD_PARAM;

Libraries/PeriphDrivers/Source/SPI/spi_reva2.c

@@ -581,6 +581,10 @@ int MXC_SPI_RevA2_SetFrequency(mxc_spi_reva_regs_t *spi, uint32_t freq)
     int hi_clk, lo_clk, scale;
     uint32_t freq_div;
 
+    if (!freq) {
+        return E_BAD_PARAM;
+    }
+
     // Check if frequency is too high
     if (freq > PeripheralClock) {
         return E_BAD_PARAM;