kselftest/arm64: Align zt-test register dumps

The zt-test output is awkward to read, as the 'Expected' value isn't
dumped on its own line and isn't aligned with the 'Got' value beneath.
For example:

Mismatch: PID=5281, iteration=3270249 Expected [00a1146901a1146902a1146903a1146904a1146905a1146906a1146907a1146908a1146909a114690aa114690ba114690ca114690da114690ea114690fa11469]
Got [00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000]
SVCR: 2

Add a newline, matching the other FPSIMD/SVE/SME tests, so that we get
output that can be read more easily:

Mismatch: PID=5281, iteration=3270249
Expected [00a1146901a1146902a1146903a1146904a1146905a1146906a1146907a1146908a1146909a114690aa114690ba114690ca114690da114690ea114690fa11469]
Got [00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000]
SVCR: 2

Admittedly this isn't all that important when the 'Got' value is all
zeroes, but otherwise this would be a major help for identifying which
portion of the 'Got' value is not as expected.

Signed-off-by: Mark Rutland <[e-mail]>
Cc: Mark Brown <[e-mail]>
Cc: Shuah Khan <[e-mail]>
Cc: Will Deacon <[e-mail]>
Cc: [e-mail]
Cc: [e-mail]
Reviewed-by: Mark Brown <[e-mail]>
Signed-off-by: Catalin Marinas <[e-mail]>

tools/testing/selftests/arm64/fp/zt-test.S

···
 	bl	putdec
 	puts	", iteration="
 	mov	x0, x22
-	bl	putdec
+	bl	putdecn
 	puts	"\tExpected ["
 	mov	x0, x10
 	mov	x1, x12