KVM: PPC: Book3S HV: Expose timing functions to module code

The next patch adds new timing points to the P9 entry path, some of
which are in the module code, so we need to export the timing
functions.

Signed-off-by: Fabiano Rosas <farosas@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20220525130554.2614394-5-farosas@linux.ibm.com