i2c: fsl_i2c: Remove inline declarations

Some functions in the fsl_i2c driver are declared as inline, even though
they are quite large, which needlessly increases the size of the
resulting binary.

This patch removes the inline declarations.

Reviewed-by: Heiko Schocher <hs@denx.de>
Signed-off-by: Mario Six <mario.six@gdsys.cc>