stmhal/i2c: Remove use of legacy I2C_NOSTRETCH_DISABLED option.

In the new HAL this is renamed to I2C_NOSTRETCH_DISABLE.

stmhal/accel.c

@@ -69,7 +69,7 @@ STATIC void accel_start(void) {
     I2CHandle1.Init.DualAddressMode = I2C_DUALADDRESS_DISABLED;
     I2CHandle1.Init.DutyCycle       = I2C_DUTYCYCLE_16_9;
     I2CHandle1.Init.GeneralCallMode = I2C_GENERALCALL_DISABLED;
-    I2CHandle1.Init.NoStretchMode   = I2C_NOSTRETCH_DISABLED;
+    I2CHandle1.Init.NoStretchMode   = I2C_NOSTRETCH_DISABLE;
     I2CHandle1.Init.OwnAddress1     = PYB_I2C_MASTER_ADDRESS;
     I2CHandle1.Init.OwnAddress2     = 0xfe; // unused
     i2c_init(&I2CHandle1);

stmhal/i2c.c

@@ -45,14 +45,6 @@
 #define MICROPY_HW_I2C_BAUDRATE_MAX 400000
 #endif
 
-#if !defined(I2C_NOSTRETCH_DISABLE)
-// Assumes that the F7 firmware is newer, so the F4 firmware will eventually
-// catchup. I2C_NOSTRETCH_DISABLED was renamed to I2C_NOSTRETCH_DISABLE
-// in the F7 so we use the F7 constant and provide a backwards compatabilty
-// #define here.
-#define I2C_NOSTRETCH_DISABLE I2C_NOSTRETCH_DISABLED
-#endif
-
 /// \moduleref pyb
 /// \class I2C - a two-wire serial protocol
 ///
@@ -503,7 +495,6 @@ STATIC mp_obj_t pyb_i2c_init_helper(const pyb_i2c_obj_t *self, mp_uint_t n_args,
     init->AddressingMode  = I2C_ADDRESSINGMODE_7BIT;
     init->DualAddressMode = I2C_DUALADDRESS_DISABLED;
     init->GeneralCallMode = args[3].u_bool ? I2C_GENERALCALL_ENABLED : I2C_GENERALCALL_DISABLED;
-    init->NoStretchMode   = I2C_NOSTRETCH_DISABLED;
     init->OwnAddress2     = 0; // unused
     init->NoStretchMode   = I2C_NOSTRETCH_DISABLE;