ftrace: Remove duplicate code for 64 and 32 bit in recordmcount.c

The elf reader for recordmcount.c had duplicate functions for both
32 bit and 64 bit elf handling. This was due to the need of using
the 32 and 64 bit elf structures.

This patch consolidates the two by using macros to define the 32
and 64 bit names in a recordmcount.h file, and then by just defining
a RECORD_MCOUNT_64 macro and including recordmcount.h twice we
create the funtions for both the 32 bit version as well as the
64 bit version using one code source.

Cc: John Reiser <[email protected]>
Signed-off-by: Steven Rostedt <[email protected]>