stmhal: Add stm32fxxx_hal_i2s_ex.c to hal/f2 (dummy) and hal/f4.

99a21dc0 · Damien George · abc24c18 · 99a21dc0 · 99a21dc0
Commit 99a21dc0 authored Jul 21, 2015 by Damien George
--- a/stmhal/hal/f2/src/stm32f2xx_hal_i2s_ex.c
+++ b/stmhal/hal/f2/src/stm32f2xx_hal_i2s_ex.c
+// dummy file to keep build system homogeneous across MCU series
--- a/stmhal/hal/f4/src/stm32f4xx_hal_i2s_ex.c
+++ b/stmhal/hal/f4/src/stm32f4xx_hal_i2s_ex.c