Modify type of variable in OPENSSL_cpuid_setup function

CLA: trivial
Reviewed-by: NKurt Roeckx <kurt@roeckx.be>
Reviewed-by: NRich Salz <rsalz@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/3651)

crypto/armcap.c

@@ -97,7 +97,7 @@ static unsigned long (*getauxval) (unsigned long) = NULL;
 
 void OPENSSL_cpuid_setup(void)
 {
-    char *e;
+    const char *e;
     struct sigaction ill_oact, ill_act;
     sigset_t oset;
     static int trigger = 0;