ath10k: miscellaneous checkpatch fixes

Fixes checkpatch warnings:

ath10k/htc.c:49: WARNING: Possible unnecessary 'out of memory' message
ath10k/htc.c:810: WARNING: Possible unnecessary 'out of memory' message
ath10k/htt.h:1034: CHECK: Please use a blank line after function/struct/union/enum declarations
ath10k/htt_rx.c:135: CHECK: Unnecessary parentheses around htt->rx_ring.alloc_idx.vaddr
ath10k/htt_rx.c:173: CHECK: Unnecessary parentheses around htt->rx_ring.alloc_idx.vaddr
ath10k/pci.c:633: WARNING: macros should not use a trailing semicolon
ath10k/wmi.c:3594: WARNING: quoted string split across lines

Signed-off-by: Kalle Valo <kvalo@qca.qualcomm.com>