drm/i915/perf: replace idr_init() by idr_init_base()

idr_init() uses base 0 which is an invalid identifier. The new function
idr_init_base allows IDR to set the ID lookup from base 1. This avoids
all lookups that otherwise starts from 0 since 0 is always unused.

References: commit 6ce711f2 ("idr: Make 1-based IDRs more efficient")

Signed-off-by: Deepak R Varma <mh12gx2825@gmail.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20201104150339.GA68663@localhost