A recent patch to create common helper functions for modem control
lines created empty helper functions in a header file, but accidentally
did not mark them as 'static inline', which causes build errors:
drivers/tty/serial/mxs-auart.o: In function `mctrl_gpio_enable_ms':
mxs-auart.c:(.text+0x171c): multiple definition of `mctrl_gpio_enable_ms'
drivers/tty/serial/clps711x.o:clps711x.c:(.text+0x768): first defined here
drivers/tty/serial/mxs-auart.o: In function `mctrl_gpio_disable_ms':
mxs-auart.c:(.text+0x1720): multiple definition of `mctrl_gpio_disable_ms'
drivers/tty/serial/clps711x.o:clps711x.c:(.text+0x76c): first defined here
This adds the missing annotation, so the functions do not get placed
in each object file.