[action] [PR:22909] [FRR]: Fix compiler warnings

[mssonicbld]

When compiling FRR, the compiler raises the following warnings:

../zebra/dplane_fpm_sonic.c:73:1: warning: data definition has no type or storage class
   73 | DEFAULT_SRV6_LOCALSID_FORMAT_BLOCK_LEN = 32;
      | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
../zebra/dplane_fpm_sonic.c:73:1: warning: type defaults to 'int' in declaration of 'DEFAULT_SRV6_LOCALSID_FORMAT_BLOCK_LEN' [-Wimplicit-int] ../zebra/dplane_fpm_sonic.c:74:1: warning: data definition has no type or storage class
   74 | DEFAULT_SRV6_LOCALSID_FORMAT_NODE_LEN = 16;
      | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
../zebra/dplane_fpm_sonic.c:74:1: warning: type defaults to 'int' in declaration of 'DEFAULT_SRV6_LOCALSID_FORMAT_NODE_LEN' [-Wimplicit-int] ../zebra/dplane_fpm_sonic.c:75:1: warning: data definition has no type or storage class
   75 | DEFAULT_SRV6_LOCALSID_FORMAT_FUNCTION_LEN = 16;
      | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
../zebra/dplane_fpm_sonic.c:75:1: warning: type defaults to 'int' in declaration of 'DEFAULT_SRV6_LOCALSID_FORMAT_FUNCTION_LEN' [-Wimplicit-int] ../zebra/dplane_fpm_sonic.c:76:1: warning: data definition has no type or storage class
   76 | DEFAULT_SRV6_LOCALSID_FORMAT_ARGUMENT_LEN = 0;
      | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
../zebra/dplane_fpm_sonic.c:76:1: warning: type defaults to 'int' in declaration of 'DEFAULT_SRV6_LOCALSID_FORMAT_ARGUMENT_LEN' [-Wimplicit-int]

The problem is that some variables have been defined without specifying their type.

This commit fixes the warnings by defining those variables as macros.

[mssonicbld]

Original PR: #22909

[mssonicbld]

/azp run Azure.sonic-buildimage

[azure-pipelines]

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