drm/i915/display: Use braces for if-ladder in intel_bw_init_hw()

drm/i915/display: Use braces for if-ladder in intel_bw_init_hw()

Looking at the current if-ladder in intel_bw_init_hw(), we see that
Xe2_HPD contains two entries, differing only for ECC memories.  Let's
improve readability by using braces and allowing adding extra conditions
for each case.

v2:
  - Tweaked commit message, since we are not going to add the ECC case
    for Xe3p_LPD anymore.

Reviewed-by: Matt Roper <matthew.d.roper@intel.com>
Link: https://patch.msgid.link/20251103-xe3p_lpd-basic-enabling-v3-3-00e87b510ae7@intel.com
Signed-off-by: Gustavo Sousa <gustavo.sousa@intel.com>