spi: atmel-quadspi: Add missing check for clk_prepare

Add check for the return value of clk_prepare() and return the error if
it fails in order to catch the error.

Fixes: 4a2f83b7 ("spi: atmel-quadspi: add runtime pm support")
Signed-off-by: Chen Ni <nichen@iscas.ac.cn>
Link: https://msgid.link/r/20240515084028.3210406-1-nichen@iscas.ac.cn


Signed-off-by: Mark Brown <broonie@kernel.org>