[SVDConv] runs in infinit loop when using generate partion on SVD file without <sauNumRegions> element under <cpu>

[pablaasmo]

Describe the bug
Given an SVD file without <device>/<CPU>/<sauNumRegions> then running svdconv --generate partition runs in loop "forever"

To Reproduce
svdconv -v --generate partition ARMCM4.svd

Expected behavior
Either generate a minimum partition_<device>.h header file, or give a warning off missing element, or do not generate header file at all.

Environment (please complete the following information):

• Tool: svdconv
• Version: v3.3.45
• OS: Linux

Additional context
Example of "runaway" generated code:

    #if defined (SAU_INIT_REGION4036008) && (SAU_INIT_REGION4036008 == 1U)
      SAU_INIT_REGION(4036008);
    #endif
    #if defined (SAU_INIT_REGION4036009) && (SAU_INIT_REGION4036009 == 1U)
      SAU_INIT_REGION(4036009);
    #endif
    #if defined (SAU_INIT_REGION4036010) && (SAU_INIT_REGION4036010 == 1U)
      SAU_INIT_REGION(4036010);

A possible cause may be that in SvdCpu.cpp the default value is set to m_sauNumRegions(SvdItem::VALUE32_NOT_INIT) where const uint32_t SvdItem::VALUE32_NOT_INIT = (uint32_t)-1;

[thorstendb-ARM]

Fixed code, thank you for the hint. Now this number gets checked also when set. Added checks / code skip and error messages where this is used.
#error "SAU Setup: Number of SAU regions not set"

see #1086