linux-firmware: Add i915 DMC firmware for Broxton

DMC provides additional graphics low-power idle states. It provides
capability to save and restore display registers across these
low-power states independently from the OS/Kernel.

This is the first release of DMC firmware for Broxton platforms.

bxt_dmc_ver1.bin is a symbolik link to latest recommended minor
release.
This major version will be just upgraded on code when it is required
software changes for API/ABI compatibility.
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>

WHENCE

@@ -2766,6 +2766,11 @@ File: i915/skl_dmc_ver1_04.bin
 File: i915/skl_dmc_ver1.bin
 Version: DMC API/ABI ver 1 - release 04 for Skylake
 
+File: i915/bxt_dmc_ver1_04.bin
+
+File: i915/bxt_dmc_ver1.bin
+Version: DMC API/ABI ver 1 - release 04 for Broxton
+
 File: i915/skl_guc_ver1_1059.bin
 
 File: i915/skl_guc_ver1.bin

i915/bxt_dmc_ver1.bin

+bxt_dmc_ver1_04.bin
\ No newline at end of file