Phytium PWM support

[xuyan213]

Generic PWM framework driver for the PWM controller found on Phytium SoCs.

[deepin-ci-robot]

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[Avenger-285714]

少了个空行嘛

[opsiff]

在 X86 上编译错误 ，之前的ARM架构宏还需要保留
drivers/pwm/sysfs.c: In function ‘pwm_export_child’:
drivers/pwm/sysfs.c:264:13: error: implicit declaration of function ‘read_cpuid_implementor’ [-Werror=implicit-function-declaration]
264 | if (read_cpuid_implementor() == ARM_CPU_IMP_PHYTIUM)
| ^~~~~~~~~~~~~~~~~~~~~~
drivers/pwm/sysfs.c:264:41: error: ‘ARM_CPU_IMP_PHYTIUM’ undeclared (first use in this function)
264 | if (read_cpuid_implementor() == ARM_CPU_IMP_PHYTIUM)
| ^~~~~~~~~~~~~~~~~~~
drivers/pwm/sysfs.c:264:41: note: each undeclared identifier is reported only once for each function it appears in
cc1: all warnings being treated as errors

[opsiff]

/ok-to-test

[deepin-ci-robot]

deepin pr auto review

Add support for Phytium SoC PWM driver

git-svn-id: 0ff597fd157e6f4fc38580e8d64ab130330d241@2142 13273008-0d34-0410-b5e6-96231b3b80d8

[opsiff]

剩余审查意见: read_cpuid_implementor方法在一个cpu中不同core有除了飞腾implementor时有其他implementor时可能失效，当前暂时无此种情况。