arm64: defconfig: ARCH_R8A7795: follow changed config symbol name

Completes commit b925adfceb52 ("soc: renesas: Add ARCH_R8A7795[01] for
existing R-Car H3") and commit 361c5dbb446e ("arm64: dts: renesas:
Remove use of ARCH_R8A7795").

CONFIG_ARCH_R8A7795 was split in CONFIG_ARCH_R8A77950 and
CONFIG_ARCH_R8A77951.

Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Max Krummenacher <[e-mail]>
Reviewed-by: Geert Uytterhoeven <[e-mail]>
Signed-off-by: Arnd Bergmann <[e-mail]>

arch/arm64/configs/defconfig

···
 CONFIG_ARCH_R8A774A1=y
 CONFIG_ARCH_R8A774B1=y
 CONFIG_ARCH_R8A774C0=y
-CONFIG_ARCH_R8A7795=y
+CONFIG_ARCH_R8A77950=y
+CONFIG_ARCH_R8A77951=y
 CONFIG_ARCH_R8A77960=y
 CONFIG_ARCH_R8A77961=y
 CONFIG_ARCH_R8A77965=y