pwm: axi-pwmgen: use shared macro for version reg

The linux/fpga/adi-axi-common.h header already defines a macro for the
version register offset. Use this macro in the axi-pwmgen driver instead
of defining it again.

Signed-off-by: David Lechner <dlechner@baylibre.com>
Link: https://lore.kernel.org/r/20240816-pwm-axi-pwmgen-use-shared-macro-v1-1-994153ebc3a7@baylibre.com


Signed-off-by: Uwe Kleine-König <ukleinek@kernel.org>