This function is not only needed by the platform suspend code, but is also
reused as the CPU resume function when the ARM cores can be powered down
completely in deep idle, which is the case on i.MX6SX and i.MX6UL(L).

Providing the static inline stub whenever CONFIG_SUSPEND is disabled means
that those platforms will hang on resume from cpuidle if suspend is disabled.

So there are two problems:

  - The static inline stub masks the linker error
  - The function is not available where needed

Fix both by just building the function unconditionally, when
CONFIG_SOC_IMX6 is enabled. The actual code is three instructions long,
so it's arguably ok to just leave it in for all i.MX6 kernel configurations.

Fixes: 05136f08 ("ARM: imx: support arm power off in cpuidle for i.mx6sx")
Signed-off-by: Lucas Stach <l.stach@pengutronix.de>
Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
Signed-off-by: Rouven Czerwinski <r.czerwinski@pengutronix.de>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>