[stm32f3discovery] some adjustments to the xml file
[stm32f3discovery] main cpu freq corrected
[stm32f3discovery] some missing definitions for the f3 in the spi arch file
[stm32f3discovery] TIMER APB2 frequency fixed
[stm32f3discovery] a missing f3 definition
[stm32f3discovery] AHB and INT_CLK corrected, some other small changes