target/arm: Un-inline access_secure_reg()

target/arm: Un-inline access_secure_reg()

We would like to move arm_el_is_aa64() to internals.h; however, it is
used by access_secure_reg().  Make that function not be inline, so
that it can stay in cpu.h.

access_secure_reg() is used only in two places:
 * in hflags.c
 * in the user-mode arm emulators, to decide whether to store
   the TLS value in the secure or non-secure banked field

The second of these is not on a super-hot path that would care about
the inlining (and incidentally will always use the NS banked field
because our user-mode CPUs never set ARM_FEATURE_EL3); put the
definition of access_secure_reg() in hflags.c, near its only use
inside target/arm.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>