Fix gdb.ada/O2_float_param.exp for PowerPC

The frame command on Power pc prints the address in hex between the
#0 and in calle.increment.  For example

(gdb) frame
#0  0x0000000010010a88 in callee.increment (val=val@entry=99.0, msg=...)
    at /home/.../gdb/testsuite/gdb.ada/O2_float_param/callee.adb:19
19	   procedure Increment (Val : in out Float; Msg: String) is

The printing of the address for the frame is done by function
print_frame in gdb/stack.c.  If SAL.IS_stmt is false for the frame,
function frame_show_address returns true and print_frame prints the
address.  Currently, SAL.IS is false on PowerPC and true on X86-64.

Update the set re string to accept the hex address if it exits.

Fixes two failures on PowerPC.

Patch tested on Power10 with no new regressions.

Approved-By: Tom Tromey <tom@tromey.com>