x86: Delete str()

This is used in an assertion only, which is somewhat dubious to begin with and
isn't expected to surivive the x86-S work (where TR is expected to become
become be a NUL selector).

Delete it now.  This avoids many cases where as a global symbol, it shadows
local string variables.

Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Acked-by: Jan Beulich <jbeulich@suse.com>
Tested-by: Nicola Vetrini <nicola.vetrini@bugseng.com>

xen/arch/x86/hvm/svm/svm.c

@@ -1614,8 +1614,6 @@ static int _svm_cpu_up(bool bsp)
     /* Initialize OSVW bits to be used by guests */
     svm_host_osvw_init();
 
-    /* Minimal checking that enough CPU setup was done by now. */
-    ASSERT(str() == TSS_SELECTOR);
     svm_vmsave_pa(per_cpu(host_vmcb, cpu));
 
     return 0;

xen/arch/x86/include/asm/desc.h

@@ -238,15 +238,6 @@ static inline void ltr(unsigned int sel)
     __asm__ __volatile__ ( "ltr %w0" :: "rm" (sel) : "memory" );
 }
 
-static inline unsigned int str(void)
-{
-    unsigned int sel;
-
-    __asm__ ( "str %0" : "=r" (sel) );
-
-    return sel;
-}
-
 #endif /* !__ASSEMBLY__ */
 
 #endif /* __ARCH_DESC_H */