[ARM] Fix test fail with conflicting -mfloat-abi

This patch fixes my earlier test case that fails for arm-none-eabi
with explicit user option for -mfloat-abi which conflict with
the test case options. I have added a guard to skip the test
on those cases.

ChangeLog entries:

*** gcc/testsuite/ChangeLog ***

2018-01-22  Sudakshina Das  <sudi.das@arm.com>

	* gcc.c-torture/compile/pr82096.c: Add dg-skip-if and
	dg-require-effective-target directives.

From-SVN: r256941

gcc/testsuite/ChangeLog

+
+2018-01-22  Sudakshina Das  <sudi.das@arm.com>
+
+	* gcc.c-torture/compile/pr82096.c: Add dg-skip-if and
+	dg-require-effective-target directives.
+
 2018-01-22  Kyrylo Tkachov  <kyrylo.tkachov@arm.com>
 
 	* lib/target-supports.exp (check_effective_target_arm_softfloat):

gcc/testsuite/gcc.c-torture/compile/pr82096.c

+/* { dg-require-effective-target arm_arch_v5t_ok { target arm*-*-* } } */
+/* { dg-skip-if "Do not combine float-abi values" { arm*-*-* } { "-mfloat-abi=*" } { "-mfloat-abi=soft" } } */
 /* { dg-additional-options "-march=armv5t -mthumb -mfloat-abi=soft" { target arm*-*-* } } */
 
 static long long AL[24];