Revert "Merge stm32-rs#131"

This reverts commit fba9834, reversing
changes made to fa3f2c2.

Author: WasabiFan

src/spi.rs

@@ -400,7 +400,7 @@ where
             nb::Error::Other(Error::ModeFault)
         } else if sr.crcerr().bit_is_set() {
             nb::Error::Other(Error::Crc)
-        } else if sr.txe().bit_is_set() && sr.bsy().bit_is_clear() {
+        } else if sr.txe().bit_is_set() {
             return Ok(());
         } else {
             nb::Error::WouldBlock
@@ -482,7 +482,7 @@ where
         }
 
         // Do one last status register check before continuing
-        nb::block!(self.check_send()).ok();
+        self.check_send().ok();
         Ok(())
     }
 }
@@ -526,7 +526,7 @@ where
         }
 
         // Do one last status register check before continuing
-        nb::block!(self.check_send()).ok();
+        self.check_send().ok();
         Ok(())
     }
 }