arm: Replace test for CONFIG_ARMV7 with CONFIG_CPU_V7

arm: Replace test for CONFIG_ARMV7 with CONFIG_CPU_V7

The arch/arm/lib/cache-cp15.c checks for CONFIG_ARMV7 and if this macro is
set, it configures TTBR0 register. This register must be configured for the
cache on ARMv7 to operate correctly.

The problem is that noone actually sets the CONFIG_ARMV7 macro and thus the
TTBR0 is not configured at all. On SoCFPGA, this produces all sorts of minor
issues which are hard to replicate, for example certain USB sticks are not
detected or QSPI NOR sometimes fails to write pages completely.

The solution is to replace CONFIG_ARMV7 test with CONFIG_CPU_V7 one. This is
correct because the code which added the test(s) for CONFIG_ARMV7 was added
shortly after CONFIG_ARMV7 was replaced by CONFIG_CPU_V7 and this code was
not adjusted correctly to reflect that change.

Signed-off-by: Marek Vasut <marex@denx.de>
Cc: Tom Rini <trini@konsulko.com>
Cc: Albert Aribaud <albert.u.boot@aribaud.net>
Cc: Simon Glass <sjg@chromium.org>