Add generic F446Rx pinout

[MCUdude]

Layout wise this pinout is more or less identical with Genric_F401Rx and Generic F411Rx, but of course designed to work with the F446Rx series.

[MCUdude]

As a note, I'm using CubeMX's clock config tool together with some of the mbed F446Rx source files to determine the right settings. I've also tested the internal and the external oscillator option on my Nucleo F446RE board

[fpistm]

AStyle failed

--- a/variants/Generic_F446Rx/variant.cpp
+++ b/variants/Generic_F446Rx/variant.cpp
@@ -154,9 +154,9 @@ static uint8_t SetSysClock_PLL_HSE(uint8_t bypass)
   }
 
   // Activate the OverDrive to reach the 180 MHz Frequency
-    if (HAL_PWREx_EnableOverDrive() != HAL_OK) {
-        return 0; // FAIL
-    }
+  if (HAL_PWREx_EnableOverDrive() != HAL_OK) {
+    return 0; // FAIL
+  }
 
   // Select PLLSAI output as USB clock source
   PeriphClkInitStruct.PLLSAI.PLLSAIM = 8;
@@ -219,7 +219,7 @@ uint8_t SetSysClock_PLL_HSI(void)
 
   // Activate the OverDrive to reach the 180 MHz Frequency
   if (HAL_PWREx_EnableOverDrive() != HAL_OK) {
-      return 0; // FAIL
+    return 0; // FAIL
   }

[fpistm]

You missed one astyle issue

--- a/variants/Generic_F446Rx/variant.cpp
+++ b/variants/Generic_F446Rx/variant.cpp
@@ -154,9 +154,9 @@ static uint8_t SetSysClock_PLL_HSE(uint8_t bypass)
   }
 
   // Activate the OverDrive to reach the 180 MHz Frequency
-    if (HAL_PWREx_EnableOverDrive() != HAL_OK) {
-      return 0; // FAIL
-    }
+  if (HAL_PWREx_EnableOverDrive() != HAL_OK) {
+    return 0; // FAIL
+  }