mtd: rawnand: gpmi: Fix suspend/resume problem

On system resume, the gpmi clock must be enabled before accessing gpmi
block.  Without this, resume causes something like

[  661.348790] gpmi_reset_block(5cbb0f7e): module reset timeout
[  661.348889] gpmi-nand 1806000.gpmi-nand: Error setting GPMI : -110
[  661.348928] PM: dpm_run_callback(): platform_pm_resume+0x0/0x44 returns -110
[  661.348961] PM: Device 1806000.gpmi-nand failed to resume: error -110

Fixes: ef347c0c

 ("mtd: rawnand: gpmi: Implement exec_op")
Cc: stable@vger.kernel.org
Signed-off-by: Esben Haabendal <esben@geanix.com>
Acked-by: Han Xu <han.xu@nxp.com>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>