[gdb/testsuite] Handle callq -> call disassembly change

[gdb/testsuite] Handle callq -> call disassembly change

We're currently running into:
...
FAIL: gdb.trace/entry-values.exp: disassemble bar
...

Since commit 36938cabf0 "x86: avoid attaching suffixes to unambiguous insns",
"callq" is disassembled as "call", and the test-case expects "callq".

Fix this by expecting "call" instead.

Tested on x86_64-linux.

gdb/testsuite/ChangeLog:

2020-07-15  Tom de Vries  <tdevries@suse.de>

	* gdb.trace/entry-values.exp: Expect "call" instead of "callq" if
	is_amd64_regs_target.