Fix comparison of unsigned long int to int in record_linux_system_call.

The if statement in case gdb_sys_ioctl in function
record_linux_system_call in file gdb/linux-record.c is as follows:

   if (tmpulongest == tdep->ioctl_FIOCLEX
      || tmpulongest == tdep->ioctl_FIONCLEX
    ....
      || tmpulongest == tdep->ioctl_TCSETSW
     ...
   }

The PowerPC ioctl value for ioctl_TCSETW is 0x802c7415.  The variable
ioctl_TCSETW is defined in gdb/linux-record.h as an int.  The TCSETW value
has the MSB set to one so it is a negative integer.  The comparison of the
unsigned long value tmpulongest to a negative integer value for
ioctl_TCSETSW fails.

This patch changes the declarations for the ioctl_* values in struct
linux_record_tdep to unsigned long to fix the comparisons between
tmpulongest and the tdep->ioctl_* values.

An additional test gdb.reverse/test_ioctl_TCSETSW.exp is added to verify
the gdb record_linux_system_call() if statement for the ioctl TCSETSW
succeeds.

This patch has been tested on Power 10 and Intel with no test failures.