chore: fix README usage example

Signed-off-by: Lachezar Lechev <elpiel93@gmail.com>

Author: elpiel

README.md

@@ -11,7 +11,7 @@ designed for readability and simplicity over performance.
 You will need something that implements the `BlockDevice` trait, which can read and write the 512-byte blocks (or sectors) from your card. If you were to implement this over USB Mass Storage, there's no reason this crate couldn't work with a USB Thumb Drive, but we only supply a `BlockDevice` suitable for reading SD and SDHC cards over SPI.
 
 ```rust
-let mut spi_dev = embedded_sdmmc::SdMmcSpi::new(embedded_sdmmc::SdMmcSpi::new(sdmmc_spi, sdmmc_cs), time_source);
+let mut spi_dev = embedded_sdmmc::SdMmcSpi::new(sdmmc_spi, sdmmc_cs);
 write!(uart, "Init SD card...").unwrap();
 match spi_dev.acquire() {
     Ok(block) => {