drm/i915/display/psr: Unset enable_psr2_sel_fetch if other checks in intel_psr2_config_valid() fails

If any of the PSR2 checks after intel_psr2_sel_fetch_config_valid()
fails, enable_psr2_sel_fetch will be kept enabled causing problems
in the functions that only checks for it and not for has_psr2.

So here moving the check that do not depend on enable_psr2_sel_fetch
and for the remaning ones jumping to a section that unset
enable_psr2_sel_fetch in case of failure to support PSR2.

Fixes: 6e43e276 ("drm/i915: Initial implementation of PSR2 selective fetch")
Cc: Jouni Högander <jouni.hogander@intel.com>
Reviewed-by: Jouni Högander <jouni.hogander@intel.com>
Signed-off-by: José Roberto de Souza <jose.souza@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220414151118.21980-1-jose.souza@intel.com