kselftest/arm64: Remove redundant _start labels from zt-test

The newly added zt-test program copied the pattern from the other FP
stress test programs of having a redundant _start label which is
rejected by clang, as we did in a parallel series for the other tests
remove the label so we can build with clang.

No functional change.

Signed-off-by: Mark Brown <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Catalin Marinas <[email protected]>

Author: broonie

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

@@ -200,7 +200,6 @@ endfunction
 // Main program entry point
 .globl _start
 function _start
-_start:
 	mov	x23, #0		// signal count
 
 	mov	w0, #SIGINT