firmware: ti_sci: Remove inline keyword from functions

The inline hint is not needed here, the compiler will do the right thing
based on if we are compiling for speed or for code size. In this case the
inline causes this function to be placed inside each callsite which is
not the right thing to do for either speed nor size. There is no
performance benefit to this due to the larger function size reducing
cache locality, but there is a huge size penalty. Remove inline keyword.

Signed-off-by: Andrew Davis <afd@ti.com>