drm/i915/tc/tgl: Implement TC cold sequences

TC ports can enter in TCCOLD to save power and is required to request
to PCODE to exit this state before use or read to TC registers.

For TGL there is a new MBOX command to do that with a parameter to ask
PCODE to exit and block TCCOLD entry or unblock TCCOLD entry.

So adding a new power domain to reuse the refcount and only allow
TC cold when all TC ports are not in use.

v2:
- fixed missing case in intel_display_power_domain_str()
- moved tgl_tc_cold_request to intel_display_power.c
- renamed TGL_TC_COLD_OFF to TGL_TC_COLD_OFF_POWER_DOMAINS
- added all TC and TBT aux power domains to
TGL_TC_COLD_OFF_POWER_DOMAINS

v3:
- added one msec sleep when PCODE returns -EAGAIN
- added timeout of 5msec to not loop forever if
sandybridge_pcode_write_timeout() keeps returning -EAGAIN

v4:
- Made failure to block or unblock TC cold a error
- removed 5msec timeout, instead giving PCODE 1msec by up 3 times to
recover from the internal error

v5:
- only sleeping 1msec when ret is -EAGAIN

BSpec: 49294
Cc: Imre Deak <imre.deak@intel.com>
Cc: Cooper Chiou <cooper.chiou@intel.com>
Cc: Kai-Heng Feng <kai.heng.feng@canonical.com>
Reviewed-by: Imre Deak <imre.deak@intel.com>
Signed-off-by: José Roberto de Souza <jose.souza@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200414194956.164323-6-jose.souza@intel.com