Remove statement is unreachable warning in MbedCRC.h

The code removed appears unnecessary given that the switch case below also
handles the case where the polynomial is `POLY_32BIT_REV_ANSI`

Author: hugueskamba

drivers/MbedCRC.h

@@ -514,11 +514,6 @@ class MbedCRC {
         MBED_STATIC_ASSERT(width <= 32, "Max 32-bit CRC supported");
 
 #if DEVICE_CRC
-        if (POLY_32BIT_REV_ANSI == polynomial) {
-            _crc_table = (uint32_t *)Table_CRC_32bit_Rev_ANSI;
-            _mode = TABLE;
-            return;
-        }
         crc_mbed_config_t config;
         config.polynomial  = polynomial;
         config.width       = width;