Modify frequency setting processing of SPI

In case of off-line compiler, there is no problem about the frequency setting processing.
But in case of online compiler, the frequency setting processing will be error.
So, modify frequency setting processing of SPI to pass in online compiler.

Author: ms-hama

libraries/mbed/targets/hal/TARGET_RENESAS/TARGET_RZ_A1H/spi_api.c

@@ -169,6 +169,8 @@ void spi_frequency(spi_t *obj, int hz) {
     uint32_t  pclk_base;
     uint32_t  div;
     uint32_t  brdv = 0;
+    uint32_t  hz_max;
+    uint32_t  hz_min;
     uint16_t  mask = 0x000c;
 
     /* set PCLK */
@@ -178,7 +180,9 @@ void spi_frequency(spi_t *obj, int hz) {
         pclk_base = CM0_RENESAS_RZ_A1_P1_CLK;
     }
 
-    if ((hz < (pclk_base / 2 / 256 / 8)) || (hz > (pclk_base / 2))) {
+    hz_min = pclk_base / 2 / 256 / 8;
+    hz_max = pclk_base / 2;
+    if ((hz < hz_min) || (hz > hz_max)) {
         error("Couldn't setup requested SPI frequency");
         return;
     }