net: stmmac: Add support for EST cycle-time-extension

Add support for cycle-time-extension. TER GCL-register needs to be
updated with the cycle-time-extension. Width of TER register is EST
time interval width + 7 bits.

Signed-off-by: Rohan G Thomas <rohan.g.thomas@intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20231201055252.1302-4-rohan.g.thomas@intel.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>