[PATCH] headers: don't depend on errno.h being available

[Francesco Dolcini]

On Thu, Jan 18, 2024 at 07:10:47PM +0100, max.oss.09 at gmail.com wrote:
> From: Max Krummenacher <max.krummenacher at toradex.com>
> 
> These headers follow the pattern:
> 
> | #if CONFIG_IS_ENABLED(FANCY_FEATURE)
> |   void foo(void);
> | #else
> |   static inline void foo(void) { return -ENOSYS; }
> | #endif
> 
> In the #else path ENOSYS is used, however linux/errno.h is not included.
> If errno.h has not been included already the compiler errors out even
> if the inline function is not referenced.
> 
> Make those headers self contained.
> 
> Signed-off-by: Max Krummenacher <max.krummenacher at toradex.com>

Reviewed-by: Francesco Dolcini <francesco.dolcini at toradex.com>