i2c: rtl9300: Drop unsupported I2C_FUNC_SMBUS_I2C_BLOCK

While applying the patch for commit ede965fd ("i2c: rtl9300: remove
broken SMBus Quick operation support"), a conflict was incorrectly solved
by adding the I2C_FUNC_SMBUS_I2C_BLOCK feature flag. But the code to handle
I2C_SMBUS_I2C_BLOCK_DATA requests will be added by a separate commit.

Fixes: ede965fd ("i2c: rtl9300: remove broken SMBus Quick operation support")
Signed-off-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>