i2c: Rename the PEC functionality bit

Rename I2C_FUNC_SMBUS_HWPEC_CALC as I2C_FUNC_SMBUS_PEC, and list that
functionality as always available through the software implementation.
Update documentation accordingly (and list similar requirements).

The way it's currently packaged doesn't present the capability in a
useful way.

Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
diff --git a/drivers/i2c/busses/i2c-i801.c b/drivers/i2c/busses/i2c-i801.c
index f78a808..ac27e5f 100644
--- a/drivers/i2c/busses/i2c-i801.c
+++ b/drivers/i2c/busses/i2c-i801.c
@@ -516,7 +516,7 @@
 	return I2C_FUNC_SMBUS_QUICK | I2C_FUNC_SMBUS_BYTE |
 	    I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_WORD_DATA |
 	    I2C_FUNC_SMBUS_BLOCK_DATA | I2C_FUNC_SMBUS_WRITE_I2C_BLOCK
-	     | (isich4 ? I2C_FUNC_SMBUS_HWPEC_CALC : 0);
+	     | (isich4 ? I2C_FUNC_SMBUS_PEC : 0);
 }
 
 static const struct i2c_algorithm smbus_algorithm = {