drm/amd/display: reduce else-if to else in dcn32_calculate_dlg_params()

cppcheck reports
drivers/gpu/drm/amd/display/dc/dml/dcn32/dcn32_fpu.c:1403:76: style:
  Expression is always true because 'else if' condition is opposite to previous condition at line 1396. [multiCondition]
   } else if (context->res_ctx.pipe_ctx[i].stream->mall_stream_config.type == SUBVP_PHANTOM) {
                                                                           ^
drivers/gpu/drm/amd/display/dc/dml/dcn32/dcn32_fpu.c:1396:69: note: first condition
   if (context->res_ctx.pipe_ctx[i].stream->mall_stream_config.type != SUBVP_PHANTOM) {
                                                                    ^
drivers/gpu/drm/amd/display/dc/dml/dcn32/dcn32_fpu.c:1403:76: note: else if condition is opposite to first condition
   } else if (context->res_ctx.pipe_ctx[i].stream->mall_stream_config.type == SUBVP_PHANTOM) {

It is not necessary to explicitly the check != condition, an else is simplier.

Fixes: 238debca ("drm/amd/display: Use DML for MALL SS and Subvp allocation calculations")
Signed-off-by: Tom Rix <trix@redhat.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>