ARM: p2v: simplify __fixup_pv_table()

Declutter the code in __fixup_pv_table() by using the new adr_l/str_l
macros to take PC relative references to external symbols, and by
using the value of PHYS_OFFSET passed in r8 to calculate the p2v
offset.

Acked-by: Nicolas Pitre <nico@fluxnic.net>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>