drm/amd/display: Remove unused dml32_CalculatedoublePipeDPPCLKAndSCLThroughput function

Remove dml32_CalculatedoublePipeDPPCLKAndSCLThroughput function, which is not used in
the codebase.

This was pointed by clang with the following warning:

drivers/gpu/drm/amd/amdgpu/../display/dc/dml/dcn32/display_mode_vba_util_32.c:393:6:
warning: no previous prototype for function
'dml32_CalculatedoublePipeDPPCLKAndSCLThroughput' [-Wmissing-prototypes]
void dml32_CalculatedoublePipeDPPCLKAndSCLThroughput(
     ^
drivers/gpu/drm/amd/amdgpu/../display/dc/dml/dcn32/display_mode_vba_util_32.c:393:1:
note: declare 'static' if the function is not intended to be used outside of
this translation unit
void dml32_CalculatedoublePipeDPPCLKAndSCLThroughput(
^
static
1 warning generated.

Reviewed-by: André Almeida <andrealmeid@igalia.com>
Signed-off-by: Maíra Canal <mairacanal@riseup.net>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>