fix(tegra): return correct error code for plat_core_pos_by_mpidr

The error code for plat_core_pos_by_mpidr() for an invalid mpidr should
be -1 as mandated by portig guide, but for tegra t186 return value is
PSCI_E_NOT_PRESENT (-7) even though the comment at top of function says
that it should return -1.

Signed-off-by: Manish Pandey <manish.pandey2@arm.com>
Change-Id: I2b69bc1a56f7966f21b2a3c89c515ebde41e3eb8
1 file changed