Update library to latest

This includes fixes for peripheral resets, introduced by library
changes:
* b3bdf025d7 stm32: i2c: drop i2c_reset()
* df654d7f28 stm32: spi: drop spi_reset()

Fixes: https://github.com/libopencm3/libopencm3-examples/issues/240

examples/stm32/f1/stm32vl-discovery/spi/spi.c

@@ -59,7 +59,7 @@ static void spi_setup(void) {
           GPIO6);
 
   /* Reset SPI, SPI_CR1 register cleared, SPI is disabled */
-  spi_reset(SPI1);
+  rcc_periph_reset_pulse(RST_SPI1);
 
   /* Set up SPI in Master mode with:
    * Clock baud rate: 1/64 of peripheral clock frequency