hexagon: Move kernel prototypes out of uapi/asm/setup.h header

The kernel function prototypes are of no use for userspace and
shouldn't get exposed in an uapi header, so let's move them into
an internal header instead.

Signed-off-by: Thomas Huth <thuth@redhat.com>
Link: https://lore.kernel.org/r/20240502173818.58152-1-thuth@redhat.com


Signed-off-by: Brian Cain <bcain@quicinc.com>
Signed-off-by: Brian Cain <brian.cain@oss.qualcomm.com>