arm64: remove unnecessary ifdefs around is_compat_task()

arm64: remove unnecessary ifdefs around is_compat_task()

Currently some parts of the codebase will test for CONFIG_COMPAT before
testing is_compat_task().

is_compat_task() is a inlined function only present on CONFIG_COMPAT.
On the other hand, for !CONFIG_COMPAT, we have in linux/compat.h:

 #define is_compat_task() (0)

Since we have this define available in every usage of is_compat_task() for
!CONFIG_COMPAT, it's unnecessary to keep the ifdefs, since the compiler is
smart enough to optimize-out those snippets on CONFIG_COMPAT=n

This requires some regset code as well as a few other defines to be made
available on !CONFIG_COMPAT, so some symbols can get resolved before
getting optimized-out.

Signed-off-by: Leonardo Bras <leobras@redhat.com>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Link: https://lore.kernel.org/r/20240109034651.478462-2-leobras@redhat.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>